See tutors' answers!

Algebra ->  Tutoring on algebra.com -> See tutors' answers!      Log On


   
By Tutor
 | By Problem Number | 

Tutor:
New! Get regular updates about newly solved problems via algebra.com's RSS system.

Recent problems solved by 'ankor@dixie-net.com'

ankor@dixie-net.com answered: 15630 problems
Jump to solutions: 0..29 , 30..59 , 60..89 , 90..119 , 120..149 , 150..179 , 180..209 , 210..239 , 240..269 , 270..299 , 300..329 , 330..359 , 360..389 , 390..419 , 420..449 , 450..479 , 480..509 , 510..539 , 540..569 , 570..599 , 600..629 , 630..659 , 660..689 , 690..719 , 720..749 , 750..779 , 780..809 , 810..839 , 840..869 , 870..899 , 900..929 , 930..959 , 960..989 , 990..1019 , 1020..1049 , 1050..1079 , 1080..1109 , 1110..1139 , 1140..1169 , 1170..1199 , 1200..1229 , 1230..1259 , 1260..1289 , 1290..1319 , 1320..1349 , 1350..1379 , 1380..1409 , 1410..1439 , 1440..1469 , 1470..1499 , 1500..1529 , 1530..1559 , 1560..1589 , 1590..1619 , 1620..1649 , 1650..1679 , 1680..1709 , 1710..1739 , 1740..1769 , 1770..1799 , 1800..1829 , 1830..1859 , 1860..1889 , 1890..1919 , 1920..1949 , 1950..1979 , 1980..2009 , 2010..2039 , 2040..2069 , 2070..2099 , 2100..2129 , 2130..2159 , 2160..2189 , 2190..2219 , 2220..2249 , 2250..2279 , 2280..2309 , 2310..2339 , 2340..2369 , 2370..2399 , 2400..2429 , 2430..2459 , 2460..2489 , 2490..2519 , 2520..2549 , 2550..2579 , 2580..2609 , 2610..2639 , 2640..2669 , 2670..2699 , 2700..2729 , 2730..2759 , 2760..2789 , 2790..2819 , 2820..2849 , 2850..2879 , 2880..2909 , 2910..2939 , 2940..2969 , 2970..2999 , 3000..3029 , 3030..3059 , 3060..3089 , 3090..3119 , 3120..3149 , 3150..3179 , 3180..3209 , 3210..3239 , 3240..3269 , 3270..3299 , 3300..3329 , 3330..3359 , 3360..3389 , 3390..3419 , 3420..3449 , 3450..3479 , 3480..3509 , 3510..3539 , 3540..3569 , 3570..3599 , 3600..3629 , 3630..3659 , 3660..3689 , 3690..3719 , 3720..3749 , 3750..3779 , 3780..3809 , 3810..3839 , 3840..3869 , 3870..3899 , 3900..3929 , 3930..3959 , 3960..3989 , 3990..4019 , 4020..4049 , 4050..4079 , 4080..4109 , 4110..4139 , 4140..4169 , 4170..4199 , 4200..4229 , 4230..4259 , 4260..4289 , 4290..4319 , 4320..4349 , 4350..4379 , 4380..4409 , 4410..4439 , 4440..4469 , 4470..4499 , 4500..4529 , 4530..4559 , 4560..4589 , 4590..4619 , 4620..4649 , 4650..4679 , 4680..4709 , 4710..4739 , 4740..4769 , 4770..4799 , 4800..4829 , 4830..4859 , 4860..4889 , 4890..4919 , 4920..4949 , 4950..4979 , 4980..5009 , 5010..5039 , 5040..5069 , 5070..5099 , 5100..5129 , 5130..5159 , 5160..5189 , 5190..5219 , 5220..5249 , 5250..5279 , 5280..5309 , 5310..5339 , 5340..5369 , 5370..5399 , 5400..5429 , 5430..5459 , 5460..5489 , 5490..5519 , 5520..5549 , 5550..5579 , 5580..5609 , 5610..5639 , 5640..5669 , 5670..5699 , 5700..5729 , 5730..5759 , 5760..5789 , 5790..5819 , 5820..5849 , 5850..5879 , 5880..5909 , 5910..5939 , 5940..5969 , 5970..5999 , 6000..6029 , 6030..6059 , 6060..6089 , 6090..6119 , 6120..6149 , 6150..6179 , 6180..6209 , 6210..6239 , 6240..6269 , 6270..6299 , 6300..6329 , 6330..6359 , 6360..6389 , 6390..6419 , 6420..6449 , 6450..6479 , 6480..6509 , 6510..6539 , 6540..6569 , 6570..6599 , 6600..6629 , 6630..6659 , 6660..6689 , 6690..6719 , 6720..6749 , 6750..6779 , 6780..6809 , 6810..6839 , 6840..6869 , 6870..6899 , 6900..6929 , 6930..6959 , 6960..6989 , 6990..7019 , 7020..7049 , 7050..7079 , 7080..7109 , 7110..7139 , 7140..7169 , 7170..7199 , 7200..7229 , 7230..7259 , 7260..7289 , 7290..7319 , 7320..7349 , 7350..7379 , 7380..7409 , 7410..7439 , 7440..7469 , 7470..7499 , 7500..7529 , 7530..7559 , 7560..7589 , 7590..7619 , 7620..7649 , 7650..7679 , 7680..7709 , 7710..7739 , 7740..7769 , 7770..7799 , 7800..7829 , 7830..7859 , 7860..7889 , 7890..7919 , 7920..7949 , 7950..7979 , 7980..8009 , 8010..8039 , 8040..8069 , 8070..8099 , 8100..8129 , 8130..8159 , 8160..8189 , 8190..8219 , 8220..8249 , 8250..8279 , 8280..8309 , 8310..8339 , 8340..8369 , 8370..8399 , 8400..8429 , 8430..8459 , 8460..8489 , 8490..8519 , 8520..8549 , 8550..8579 , 8580..8609 , 8610..8639 , 8640..8669 , 8670..8699 , 8700..8729 , 8730..8759 , 8760..8789 , 8790..8819 , 8820..8849 , 8850..8879 , 8880..8909 , 8910..8939 , 8940..8969 , 8970..8999 , 9000..9029 , 9030..9059 , 9060..9089 , 9090..9119 , 9120..9149 , 9150..9179 , 9180..9209 , 9210..9239 , 9240..9269 , 9270..9299 , 9300..9329 , 9330..9359 , 9360..9389 , 9390..9419 , 9420..9449 , 9450..9479 , 9480..9509 , 9510..9539 , 9540..9569 , 9570..9599 , 9600..9629 , 9630..9659 , 9660..9689 , 9690..9719 , 9720..9749 , 9750..9779 , 9780..9809 , 9810..9839 , 9840..9869 , 9870..9899 , 9900..9929 , 9930..9959 , 9960..9989 , 9990..10019 , 10020..10049 , 10050..10079 , 10080..10109 , 10110..10139 , 10140..10169 , 10170..10199 , 10200..10229 , 10230..10259 , 10260..10289 , 10290..10319 , 10320..10349 , 10350..10379 , 10380..10409 , 10410..10439 , 10440..10469 , 10470..10499 , 10500..10529 , 10530..10559 , 10560..10589 , 10590..10619 , 10620..10649 , 10650..10679 , 10680..10709 , 10710..10739 , 10740..10769 , 10770..10799 , 10800..10829 , 10830..10859 , 10860..10889 , 10890..10919 , 10920..10949 , 10950..10979 , 10980..11009 , 11010..11039 , 11040..11069 , 11070..11099 , 11100..11129 , 11130..11159 , 11160..11189 , 11190..11219 , 11220..11249 , 11250..11279 , 11280..11309 , 11310..11339 , 11340..11369 , 11370..11399 , 11400..11429 , 11430..11459 , 11460..11489 , 11490..11519 , 11520..11549 , 11550..11579 , 11580..11609 , 11610..11639 , 11640..11669 , 11670..11699 , 11700..11729 , 11730..11759 , 11760..11789 , 11790..11819 , 11820..11849 , 11850..11879 , 11880..11909 , 11910..11939 , 11940..11969 , 11970..11999 , 12000..12029 , 12030..12059 , 12060..12089 , 12090..12119 , 12120..12149 , 12150..12179 , 12180..12209 , 12210..12239 , 12240..12269 , 12270..12299 , 12300..12329 , 12330..12359 , 12360..12389 , 12390..12419 , 12420..12449 , 12450..12479 , 12480..12509 , 12510..12539 , 12540..12569 , 12570..12599 , 12600..12629 , 12630..12659 , 12660..12689 , 12690..12719 , 12720..12749 , 12750..12779 , 12780..12809 , 12810..12839 , 12840..12869 , 12870..12899 , 12900..12929 , 12930..12959 , 12960..12989 , 12990..13019 , 13020..13049 , 13050..13079 , 13080..13109 , 13110..13139 , 13140..13169 , 13170..13199 , 13200..13229 , 13230..13259 , 13260..13289 , 13290..13319 , 13320..13349 , 13350..13379 , 13380..13409 , 13410..13439 , 13440..13469 , 13470..13499 , 13500..13529 , 13530..13559 , 13560..13589 , 13590..13619 , 13620..13649 , 13650..13679 , 13680..13709 , 13710..13739 , 13740..13769 , 13770..13799 , 13800..13829 , 13830..13859 , 13860..13889 , 13890..13919 , 13920..13949 , 13950..13979 , 13980..14009 , 14010..14039 , 14040..14069 , 14070..14099 , 14100..14129 , 14130..14159 , 14160..14189 , 14190..14219 , 14220..14249 , 14250..14279 , 14280..14309 , 14310..14339 , 14340..14369 , 14370..14399 , 14400..14429 , 14430..14459 , 14460..14489 , 14490..14519 , 14520..14549 , 14550..14579 , 14580..14609 , 14610..14639 , 14640..14669 , 14670..14699 , 14700..14729 , 14730..14759 , 14760..14789 , 14790..14819 , 14820..14849 , 14850..14879 , 14880..14909 , 14910..14939 , 14940..14969 , 14970..14999 , 15000..15029 , 15030..15059 , 15060..15089 , 15090..15119 , 15120..15149 , 15150..15179 , 15180..15209 , 15210..15239 , 15240..15269 , 15270..15299 , 15300..15329 , 15330..15359 , 15360..15389 , 15390..15419 , 15420..15449 , 15450..15479 , 15480..15509 , 15510..15539 , 15540..15569 , 15570..15599 , 15600..15629 , 15630..15659, >>Next

Sequences-and-series/222358: hey there thanks ,the question is-
the difference between two numbers is 4 and the sum of their squares is80 less than three times their product. Find the numbers
thanks again.
xx

1 solutions

Answer 166605 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 15:45:55 (Show Source):
You can put this solution on YOUR website!
the difference between two numbers is 4
x - y = 4
or
x = (y + 4)
:
"the sum of their squares is 80 less than three times their product."
x^2 + y^2 = 3xy - 80
x^2 - 3xy + y^2 = -80
;
replace x with (y+4)
(y+4)^2 - 3y(y+4) + y^2 = -80
y^2 + 8y + 16 - 3y^2 - 12y + y^2 = -80
:
Combine like terms
y^2 + y^2 - 3y^2 + 8y - 12y + 16 + 80 = 0
:
-y^2 - 4y + 96 = 0
:
Multiply by -1
y^2 + 4y - 96 = 0
:
Factor:
(y+12)(y-8) = 0
:
Positive solution
y = 8
find x
x = 8 + 4
x = 12
:
Check
12^2 + 8^2 = 3*12*8 - 80
144 + 64 = 288 - 80
208 = 208
:
:
How about the solution y = -12?
then
x = -12 - 4
x = -16
:
-16^2 + -12^2 = 3*-16*-12 - 80
256 + 144 = 576 - 80
not a solution







Percentage-and-ratio-word-problems/222147: If a 5'10" man is 350% of his length as a newborn baby, how many inches long was he when he was born?
1 solutions

Answer 166592 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 15:16:35 (Show Source):
You can put this solution on YOUR website!
If a 5'10" man is 350% of his length as a newborn baby,
how many inches long was he when he was born?
:
Convert 5'10" to inches: 5*12 + 10 = 70 inches
:
Let b = length of baby
3.5b = 70
b = 70%2F3.5
b = 20" long


Inequalities/222057: adele went to the post office to buy stamps and postcards. she bought a total of 25 stamps some 39 cent stamps and the rest 23 cent postcards. if she paid $8.47 altogether, how many 39 cent stamps did she buy?
1 solutions

Answer 166589 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 14:59:00 (Show Source):
You can put this solution on YOUR website!
she bought a total of 25 stamps some 39 cent stamps and the rest 23 cent postcards.
if she paid $8.47 altogether, how many 39 cent stamps did she buy?
:
Let s = no. of 39 cent stamps
and
Let p = no. of 23 cent stamps
;
write an equation for each statement:
:
"she bought a total of 25 stamps some 39 cent stamps and the rest 23 cent"
s + p = 25
arrange for use as substitution
p = (25-s)
:
"if she paid $8.47 altogether," let's just deal in cents
39s + 23p = 847
:
Replace p with (25-s) in the above equation, find s
39s + 23(25-s) = 847
39s + 575 - 23s = 847
39s - 23s = 847 - 575
16s = 272
s = 272%2F16
s = 17 ea 39 cent stamps
and
25 - 17 = 8 ea 23 cent stamps
;
;
Is this true?
.39(17) + .23(8) =
6.63 + 1.84 = 8.47, seems to be



Numbers_Word_Problems/222054: what is the answer to this word problem
"The Difference between two numbers is 16. Five times the smaller is the same as 8 less than twice the larger. find the numbers?"

And this one also please,

The sum of two numbers is the same as four times the smaller number, if twice the larger is decreased by the smaller, the result is 30. find the numbers?
1 solutions

Answer 166585 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 14:43:50 (Show Source):
You can put this solution on YOUR website!
I am going to do better than give you the answer, I am going to show you how to do it.
:
write an equation for each statement, let the numbers be x & y
:
"The Difference between two numbers is 16."
x - y = 16
Arrange this to be used for substitution
x = y + 16
:
Five times the smaller is the same as 8 less than twice the larger."
5y = 2x - 8
:
Replace x in the above with (y+16). find y
5y = 2(y+16) - 8
5y = 2y + 32 - 8
5y - 2y = 24
3y = 24
y = 24%2F3
y = 8
:
You should be able to find x now
;
:
"The sum of two numbers is the same as four times the smaller number,"
x + y = 4y
x = 4y - y
x = 3y
:
"twice the larger is decreased by the smaller, the result is 30.
2x - y = 30
:
Replace x with 3y in the above
2(3y) - y = 30
6y - y = 30
5y = 30
You should be able to handle it now.


Polynomials-and-rational-expressions/222153: Can someone please assist me with this equation? I need to find the GCF but I am not sure what to do after that point.
22uw^7z^8 and 20u^3w^4
I believe the GCF is 2
this one find the least common multiple
8tuz^9 and 2t^3u^7 (this one has me completely lost)
1 solutions

Answer 166581 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 14:31:00 (Show Source):
You can put this solution on YOUR website!
find the GCF
22uw^7z^8 and 20u^3w^4
:
2uw^4 would be the GCF
:
2uw^4(11w^3z^8) and 2uw^4(10u^2)
;
:
least common multiple
8tuz^9 and 2t^3u^7
:
Each term has to go into the multiple at least 1 time, so that would be:
8t^3u^7z^9


Travel_Word_Problems/222018: Juan drives to work. Because of traffic conditions, he averages 22 mph. He retunrs home averaging 32 mph. The total travel time is 2 1/4 hours. Write the equation to find the time Juan spends driving to work.
1 solutions

Answer 166574 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 14:20:40 (Show Source):
You can put this solution on YOUR website!
Because of traffic conditions, he averages 22 mph.
He returns home averaging 32 mph.
The total travel time is 2 1/4 hours.
Write the equation to find the time Juan spends driving to work.
:
Change 21%2F4 hrs to 2.25 hrs
:
Let t = His time to work
then
(2.25-t) = His time from work
:
Distance and to and from is equal. Write a distance equation and find t
22t = 32(2.25-t)


Graphs/222022: okay, i just dont know how to graph this problem.
|n+8|>=3
my work was:
n+8>=3 n+8>=-3
-8 -8 -8 -8
n>=-5 n>=-11
now what?
1 solutions

Answer 166567 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 14:12:49 (Show Source):
You can put this solution on YOUR website!
|n+8| > = 3
my work was:
n + 8 > = 3; this right, so you have;
n >= 3 -8
n >= -5 which you have
and
n + 8 <= -3; when you make 3 negative, you have to reverse the inequality sign
n <= -3 - 8
n <= -11
:
The solution:
n >= -5
n <= -11
:
:
Note that any value between -11 and -5 would not satisfy the inequality
But any value below -11 and above -5 would satisfy



Finance/222144: I need help in my algebra class setting up this word problem.
Jake invested $6,000, part at 6% simple interest and part at 4%simple interest for a period of 1 year. How much did she invest at each rate if each account earned the same interest?

1 solutions

Answer 166556 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 13:49:32 (Show Source):
You can put this solution on YOUR website!
Jake invested $6,000, part at 6% simple interest and part at 4%simple interest for a period of 1 year.
How much did she invest at each rate if each account earned the same interest?
;
Let x = amt invested at 6%
then
(6000-x) = amt invested a 4%
:
int at 6% = int at 4%
.06x = .04(6000-x)
.06x = 240 - .04x
.06x + .04x = 240
.10x = 240
x = 240%2F.1
x = $2400 invested at 6%
then
6000 - 2400 = $3600 invested at 4%
;
:
Check solution by find that amt of interest earned by each
.06(2400) = $144
.04(3600) = $144


Equations/222031: I have a graph that shows the wind speed for an F4 Tornado is 207-260mph. My question is:
Write a pair of inequalities that best represents the wind speed (w) for an F4 tornado.
Is the answer w207-w260?
1 solutions

Answer 166553 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 13:43:05 (Show Source):
You can put this solution on YOUR website!
Write a pair of inequalities that best represents the wind speed (w) for an F4 tornado.
wouldn't be:
w =< 260
and
w => 207


Polynomials-and-rational-expressions/222189: factor completely 27x^3+125
1 solutions

Answer 166545 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 13:29:02 (Show Source):
You can put this solution on YOUR website!
27x^3 + 125
:
You can see both coefficients are perfect cubes, 3 and 5
:
Use the special factoring form for the "sum of cubes" (x + y)(x^2 - xy + y^2)
:
In this problem:
(3x + 5)(9x^2 - 15x + 25)


Numbers_Word_Problems/222026: find four consecutive ODD integers such that four less than twice the second has the same value as three times the number that is one more than the third.
1 solutions

Answer 166535 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 13:06:01 (Show Source):
You can put this solution on YOUR website!
find four consecutive ODD integers
x, x+2, x+4, x+6
;
such that four less than twice the second has the same value as three times the number that is one more than the third.
2(x+2) - 4 = 3((x+4)+1)
2x + 4 - 4 = 3(x+5)
2x = 3x + 15
-15 = 3x - 2x
x = -15
:
The four numbers: -15, -13, -11, -9
:
:
Check solution in the given statement:
"four less than twice the second has the same value as three times the number that is one more than the third."
2(-13) - 4 = 3(-11 + 1)
-26 - 4 = 3(-10)


Miscellaneous_Word_Problems/221967: two trains depart from a station, traveling in opposite directions. the train that departs at 6:30 AM travels 15 km/h faster than the train that departs at 6 AM. At 7 AM they are 135 km apart. Determine the rate of each train.
1 solutions

Answer 166500 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 09:57:27 (Show Source):
You can put this solution on YOUR website!
two trains depart from a station, traveling in opposite directions.
the train that departs at 6:30 AM travels 15 km/h faster than the train that
departs at 6 AM. At 7 AM they are 135 km apart.
Determine the rate of each train.
:
Let s = speed of the train that departs at 6 AM
then
(s+15) = speed of the train that departs at 6:30
:
At 7 AM:
the 1st train travel time is 1 hr
the 2nd train travel time is .5 hr
:
Write a distance equation: Dist = time * speed
:
1s + .5(s+15) = 135
1s + .5s + 7.5 = 135
1s + .5s = 135 - 7.5
1.5s = 127.5
s = 127.5%2F1.5
s = 85 mph is the speed of the 6 AM train
:
85 + 15 = 100 mph is the speed of the 6:30 train
;
;
Check solution in the distance equation
1*85 + .5*100 =
85 + 50 = 135


Linear-systems/222186: Solve the system by the addition method showing all work:
(1/6)x + (1/4)y = -2
x – y = -6

1 solutions

Answer 166499 by ankor@dixie-net.com(15645) About Me  on 2009-10-06 08:48:52 (Show Source):
You can put this solution on YOUR website!
Solve the system by the addition method showing all work:
(1/6)x + (1/4)y = -2
x – y = -6
multiply the 1st equation by 4. In the 2nd equation change coefficient of x to 6/6
4%2F6x + y = -8
6%2F6x - y = - 6
-----------------addition eliminates y and you have:
10%2F6x = -14
Multiply both sides by 6
10x = 6(-14)
10x = -84
x = %28-84%29%2F10
x = -8.4
:
Find y using x - y = -6
-8.4 - y = -6
Multiply equation by -1
8.4 + y = 6
y = 6 - 8.4
y = -2.4
;
:
Check solution in the 1st equation
(1/6)(-8.4) + (1/4)(-2.4) = -2
-1.4 + -.6 = -2


Length-and-distance/222064: please help me find this answer.
A is the midpoint of segment DE, and DA=12. I and N are trisection points of segment DE. Find segment AN.
There is also a diagram that shows a line and points which are in this order: D, I, A, N, E.
1 solutions

Answer 166438 by ankor@dixie-net.com(15645) About Me  on 2009-10-05 21:35:10 (Show Source):
You can put this solution on YOUR website!
A is the midpoint of segment DE, and DA=12. I and N are trisection points of segment DE. Find segment AN.
There is also a diagram that shows a line and points which are in this order: D, I, A, N, E.
:
From the information given we know that DE = 2*12 = 24
Trisect 24: 24/3 = 8
:
If D=0, I=8, A=12, N=16, E= 24
therefore
AN = 4


Travel_Word_Problems/222063: Debbie traveled by Boat 5 miles upstream to fish. Because of the 4mph current, it took her 20 minutes longer to get there than to return. How fast will her boat go in still water?
1 solutions

Answer 166436 by ankor@dixie-net.com(15645) About Me  on 2009-10-05 21:23:08 (Show Source):
You can put this solution on YOUR website!
Debbie traveled by boat 5 miles upstream to fish.
Because of the 4 mph current, it took her 20 minutes longer to get there
than to return.
How fast will her boat go in still water?
:
Let s = boat speed in still water
then
(s-4) = speed upstream
and
(s+4) = speed down stream
:
Convert 20 min to hrs: 20/60 = 1%2F3hr
:
Write a time equation: time = distance%2Fspeed
Upstream time = downstream time + 20 minutes (1/3 hr)
5%2F%28%28s-4%29%29 = 5%2F%28%28s%2B4%29%29 + 1%2F3
:
To clear out these denominators, multiply equation by 3(s+4)(s-4)
3(s+4)(s-4)*5%2F%28%28s-4%29%29 = 3(s+4)(s-4)*5%2F%28%28s%2B4%29%29 + 1%2F3*3(s+4)(s-4)
Results in
:
15(s+4) = 15(s-4) + (s+4)(s-4)
:
15s + 60 = 15s - 60 + s^2 - 16
:
0 = 15s - 15s - 60 - 60 + s^2 - 16
:
0 = s^2 - 136
:
s^2 = 136
s = sqrt%28136%29
s = 11.66 mph speed in still water
:
:
Check solution on calc: (speed up = 7.66 and speed down = 15.66)
5/7.66 - 5/15.66 = .3333 which is 1/3 of an hr


Mixture_Word_Problems/222048: How many grams of pure silver must a silversmith mix with a 45% silver alloy to produce 200 grams of a 50% alloy?
1 solutions

Answer 166434 by ankor@dixie-net.com(15645) About Me  on 2009-10-05 21:16:30 (Show Source):
You can put this solution on YOUR website!
How many grams of pure silver must a silversmith mix with a 45% silver alloy to produce 200 grams of a 50% alloy?
:
Let x = amt of pure silver required to do this
Then
(200-x) = amt of 45% silver alloy required
;
x + .45(200-x) = .50(200)
:
x + 90 - .45x = 100
x - .45x = 100 - 90
.55x = 10
x = 10%2F.55
x = 18.2 grams of pure silver
:
:
Check solution: 200-18.2 = 181.8 grams of 45% silver
18.2 + .45(181.8) = .5(200)
18.2 + 81.8 = 100
100 = 100


Travel_Word_Problems/222124: Train A and B are traviling the same direction on parallel tracks. Train A is traviling at 100 miles per hour and train B is traviling at 120 miles per hour. Train A passes a station at 5:25 p.m. If train B passes the same station at 5:40 p.m., at what time will train B catch up with train A?
1 solutions

Answer 166431 by ankor@dixie-net.com(15645) About Me  on 2009-10-05 21:08:31 (Show Source):
You can put this solution on YOUR website!
Train A and B are traveling the same direction on parallel tracks.
Train A is traveling at 100 miles per hour and train B is traveling at 120 miles per hour.
Train A passes a station at 5:25 p.m.
If train B passes the same station at 5:40 p.m., at what time will train B catch up with train A?
:
from the given information, we know that train B is 15 min (.25 hr) behind
train A, when train A passes the station
:
The distance between the trains at this time: .25 * 120 = 30 mi
:
Let t = time required for train B to catch train a
:
write a distance equation: Dist = speed * time
:
Train b travel dist = Train a travel dist + 30 mi
120t = 100t + 30
120t - 100t = 30
20t = 30
t = 30%2F20
t = 1.5 hr or 1 hr 30 min
:
5:25 + 1:30 = 6:55 pm, B catches A
:
:
Check solution by finding the distances (train b travels 30 mi more than train b)
120 * 1.5 = 180 mi
100 * 1.5 = 150 mi
-------------------
difference = 30 mi


Miscellaneous_Word_Problems/221986: a rescue helicopter is flying from an aircraft carrier 350 mi to peral harbor hospital. the point of no return is the point here it would take as much time to fly back to the aircraft carrier as it would to fly on to pearl harbor. the airspeed of the helicopter is 175 mi/h and it is flying into a 25 mi/h headwind.
a. calculate the total time for the helicopter to fly to pearl harbor
b. once the helicopter is at the point of no return, determine the time it will take to complete the trip.
c. use the results from part a and b to determine the time for the helicopter to reach the point of no return.
1 solutions

Answer 166404 by ankor@dixie-net.com(15645) About Me  on 2009-10-05 19:22:23 (Show Source):
You can put this solution on YOUR website!
a rescue helicopter is flying from an aircraft carrier 350 mi to Pearl harbor hospital.
The point of no return is the point where it would take as much time to fly back
to the aircraft carrier as it would to fly on to pearl harbor.
The airspeed of the helicopter is 175 mi/h and it is flying into a 25 mi/h headwind.
a. calculate the total time for the helicopter to fly to pearl harbor
t = 350%2F%28%28175-25%29%29
t = 350%2F%28%28150%29%29
t = 21%2F3 hrs (2 hrs 20 min)
:
b. once the helicopter is at the point of no return, determine the time it will take to complete the trip.
:
Let p = point of no return (miles from carrier)
Then (350-p) = miles from Pearl Harbor
:
return to carrier = continue to Pearl
p%2F%28175%2B25%29 = %28350-p%29%2F%28175-25%29
p%2F%28200%29 = %28350-p%29%2F%28150%29
Cross multiply
150p = 200(350-p)
150p = 70000 - 200p
150p + 200p = 70000
350p = 70000
p = 70000%2F350
p = 200 mi from carrier is point of no return. (150 mi from Pearl)
:
c. use the results from part a and b to determine the time for the helicopter to reach the point of no return.
t = 200%2F%28175-25%29
t = 200%2F%28150%29
t = 11%2F3 hrs
:
:
This checks out, it would take 1 hr to cover the remaining 150 mi at 150 mph
1 + 11%2F3 = 21%2F3 as found in part a
and
to return to the carrier, with the wind, 200 mi at 200 mph = 1 hr also


Linear-equations/221859: Find three consecutive even integers such that if the largest integer is subtracted from four times the smallest , the result is 6 more than twice the sum of the two smallest integers
1 solutions

Answer 166318 by ankor@dixie-net.com(15645) About Me  on 2009-10-05 16:21:38 (Show Source):
You can put this solution on YOUR website!
Find three consecutive even integers
x, (x+2), (x+4)
:
the largest integer is subtracted from four times the smallest, the result
is 6 more than twice the sum of the two smallest integers.
:
4x - (x+4) = 2(x + (x+2)) + 6
Remove the brackets
4x - x - 4 = 2(2x+2) + 6
3x - 4 = 4x + 4 + 6
3x - 4 = 4x + 10
3x - 4x = 10 + 4
-x = 14
x = -14
:
-14, -12, -10 are the three integers
:
check solution in the statement:
"the largest integer is subtracted from four times the smallest, the result
is 6 more than twice the sum of the two smallest integers"
4(-14) - (-10) = 2(-14 + -12) + 6
-56 + 10 = 2(-26) + 6
-56 + 10 = -52 + 6
-46 = -46


Quadratic_Equations/221675: Hi, I am having a problem with a question that reads the following: Use the quadratic formula to solve the equation for x in terms of y. 8x^2-8xy+6(1-y^2)=0
Thanks in advance.

1 solutions

Answer 166312 by ankor@dixie-net.com(15645) About Me  on 2009-10-05 15:56:54 (Show Source):
You can put this solution on YOUR website!
Use the quadratic formula to solve the equation for x in terms of y.
+8x%5E2-8xy%2B6%281-y%5E2%29=+0
:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
:
In this problems a=8; b=-8y; c=6(1-y^2)

:
x+=+%288y+%2B-+sqrt%2864y%5E2+-+192%281-y%5E2%29+%29%29%2F16+
:
x+=+%288y+%2B-+sqrt%2864y%5E2+-+192+%2B+192y%5E2%29+%29%2F16+
:
x+=+%288y+%2B-+sqrt%28256y%5E2+-+192%29+%29%2F16+; combine like terms
:
x+=+%288y+%2B-+sqrt%2864%284y%5E2+-+3%29%29+%29%2F16+; factor out 64
:
x+=+%288y+%2B-+8%2Asqrt%284y%5E2+-+3%29+%29%2F16+; extract square root of 64
:
x+=+%28y+%2B-+sqrt%284y%5E2+-+3%29+%29%2F2+; divide both 8's into 16




Miscellaneous_Word_Problems/221798: Please help me solve this problem...I dont know how to start solving this..
A 10-quart container is filled with water. One quart of water is drained out and replaced with alcohol. After mixing, a quart of the soluti0n is drained out and replaced with alcohol. This process continued until 5quarts of alcohol have been put into the container. The solution in the container is then what percent of alcohol?
Thank you in advance..
1 solutions

Answer 166271 by ankor@dixie-net.com(15645) About Me  on 2009-10-05 12:47:48 (Show Source):
You can put this solution on YOUR website!
A 10-quart container is filled with water.
One quart of water is drained out and replaced with alcohol.
After mixing, a quart of the soluti0n is drained out and replaced with alcohol.
This process continued until 5quarts of alcohol have been put into the container.
The solution in the container is then what percent of alcohol?
:
try it step by step
:
After the 1st replacement, its a .1(10) mixture
:
2nd replacement:
.1(10-1) + 1 =
.1(9) + 1 =
.9 + 1 = 1.9 = 1.9 qt of alcohol
that's a 1.9%2F10 = .19(10) mixture
:
3rd replacement
.19(10-1) + 1
.19(9) + 1
1.71 + 1 = 2.71 qt of alcohol
that's 2.71%2F10 = .27(10) mixture
:
3rd replacement
.27(10-1) + 1 =
.27(9) + 1 =
2.44 + 1 = 3.44 gt of alcohol
that's 3.44%2F10 = .344(10) mixture
:
4th replacement
.344(10-1) + 1 =
.344(9) + 1 =
3.096 + 1 = 4.096 gt of alcohol
that's 4.096%2F10 = .4096(10) mixture
:
5th replacement
.4096(10-1) + 1 =
.4096(9) + 1 =
3.6864 + 1 = 4.6864 qt of alcohol
that's 4.6864%2F10 = .46864(10) mixture
:
we can say 46.864% alcohol now


Equations/221662: Hi, I am having trouble with a word problem. The problem states "When a rock is dropped from a cliff into an ocean, it travels approximately 16t^2 ft in t seconds. If the splash is heard 4.5 seconds later and the speed of sounds is 1100ft/sec, approximate the height of the cliff."
Thanks in advance.
1 solutions

Answer 166247 by ankor@dixie-net.com(15645) About Me  on 2009-10-05 08:21:04 (Show Source):
You can put this solution on YOUR website!
When a rock is dropped from a cliff into an ocean, it travels approximately 16t^2 ft in t seconds.
If the splash is heard 4.5 seconds later and the speed of sounds is 1100ft/sec, approximate the height of the cliff."
:
t = time for the rock to reach the water
then
(4.5-t) = time for the sound to reach the top of the cliff
:
Both the rock and the sound will travel the same distance.
Write a distance equation
:
16t^2 = 1100(4.5-t)
16t^2 = 4950 - 1100t
:
Arrange as a quadratic equation
16t^2 + 1100t - 4950 = 0
;
Simplify, divide by 2
8t^2 + 550t - 2475
:
Use the quadratic formula to find t:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
in this problem x=t; a=8; b=550; c=-2475
t+=+%28-550+%2B-+sqrt%28+550%5E2+-+4+%2A+8+%2A-2475+%29%29%2F%282%2A8%29+
:
t+=+%28-550+%2B-+sqrt%28302500+-+%28-72900%29+%29%29%2F%2816%29+
:
t+=+%28-550+%2B-+sqrt%28302500++%2B+72900+%29%29%2F%2816%29+
:
t+=+%28-550+%2B-+sqrt%28381700+%29%29%2F%2816%29+
we only want the positive solution here
t+=+%28-550+%2B+617.819%29%2F16+
t = 67.819%2F16
t = 4.239 sec for the rock to hit the water
and
4.5 - 4.238 = .261 sec for the sound to come back
:
:
You can use either value to find the height of the cliff
16(4.238^2) = 287 ft
and
1100(.261) = 287 ft
:
:
Make sense to you?


Equations/221380: Can someone please solve this sum for me and explain how you got to the answer?
Two cyclists start biking from a trail's start 3 hours apart. The second cyclist travels at 10 miles per hour and starts 3 hours after the first cyclist who is traveling at 6 miles per hour. How much time will pass beofre the second cyclist catches up with the first from the time the second cyclist started biking?
muchos gracias (:
1 solutions

Answer 166173 by ankor@dixie-net.com(15645) About Me  on 2009-10-04 20:20:28 (Show Source):
You can put this solution on YOUR website!
Two cyclists start biking from a trail's start 3 hours apart.
The second cyclist travels at 10 miles per hour and starts 3 hours after the
first cyclist who is traveling at 6 miles per hour.
How much time will pass before the second cyclist catches up with the first
from the time the second cyclist started biking?
;
Let t = travel time of the 2nd cyclist
then
(t+3) = travel time of the 1st cyclist
:
When the 2nd overtakes the 1st, they will have traveled the same distance.
Write a distance equation using this fact: Dist = speed * time
:
2nd cyclist dist = 1st cyclist dist
10t = 6(t+3)
10t = 6t + 18
10t - 6t = 18
4t = 18
t = 18%2F4
t = 4.5 hrs from the time the 2nd cyclist starts
;
:
Check solution by finding the distance traveled by each (should be equal)
10*4.5 = 45 mi
6*7.5 = 45 mi; confirms our solution
:
:
Answering your question about the time.
it should be apparent to you that the 1st cyclist was on the road 3 hr longer
than the 2nd cyclist "t", hence we call 1st cyclist time "t+3"


Miscellaneous_Word_Problems/221465: It takes a train 7 seconds to pass by a stationary observer and 26 seconds to travel the length of a station 380 meters long. What is the speed of the train and its length?

1 solutions

Answer 166169 by ankor@dixie-net.com(15645) About Me  on 2009-10-04 20:10:00 (Show Source):
You can put this solution on YOUR website!
It takes a train 7 seconds to pass by a stationary observer and 26 seconds to travel the length of a station 380 meters long.
What is the speed of the train and its length?
:
let s = speed of the train in meters/sec
:
7s = length of the train
:
time of the front of the train passing the platform
It passes the platform 26-7 = 19 sec
:
s = 380%2F19
s = 20 meters/sec
:
Train length = 7s
7(20) = 140 meters long
:
The speed of train in km/hr = %283600%2A20%29%2F1000 = 72 km/hr


Linear_Equations_And_Systems_Word_Problems/221258: Diophantus a greek mathematician is considered by many as the "Father of Algeria" because of his works in the syncopation of algebra. In his epitaph, the following is scripted. "A sixth of his life was spent in childhood. A twelfth as a youth, and a seventh as a bachelor. Five years after his marriage, his son was born but died four years before his own death at half his age".
1 solutions

Answer 166132 by ankor@dixie-net.com(15645) About Me  on 2009-10-04 18:00:17 (Show Source):
You can put this solution on YOUR website!
Diophantus passed one-sixth of his life in childhood, one-twelfth in youth, one-seventh more as a bachelor. Five years after his marriage, a son was born who died four years before his father, at half his father's [final] age. How old was Diophantus when he died.
:
Let x = his final age
:
a lengthy but simple equation
Final age = child + youth + bach + marriage + son's age + 4
x = 1%2F6x + 1%2F12x + 1%2F7x + 5 + 1%2F2x + 4
:
Common denominator of 12*7 = 84
x = 14%2F84x + 7%2F84x + 12%2F84x + 5 + 42%2F84x + 4
:
x = 75%2F84x + 9
:
84%2F84x - 75%2F84x = 9
:
9%2F84x = 9
:
x = 84 is his final age
:
Check:
14 + 7 + 12 + 5 + 42 + 4 = 84


Human-and-algebraic-language/221446: A colonel, on attempting to draw up his regiment in the form of a solid square, finds that he has 30 men left over, and that he would require 25 soliders in his regiment to increase the side of the square by one soldier. How many soldiers are there in the regiment?
1 solutions

Answer 166101 by ankor@dixie-net.com(15645) About Me  on 2009-10-04 16:54:00 (Show Source):
You can put this solution on YOUR website!
A colonel, on attempting to draw up his regiment in the form of a solid square,
finds that he has 30 men left over, and that he would require 25 solders in his
regiment to increase the side of the square by one soldier.
How many soldiers are there in the regiment?
;
Let (x^2 + 30) = no. of soldiers in the regiment
:
It says that 25 more would give him one more in each side:
We can write that
(x + 1)^2 = x^2 + 30 + 25
:
x^2 + 2x + 1 = x^2 + 55
;
x^2 - x^2 + 2x = 55 - 1
:
2x = 54
x = 54%2F2
x = 27
therefore
27^2 + 30 = 759 soldiers
:
Is this true?
28^2 - 759 = 25


test/221116: Rus and dufus each took some money froma piggy bank to buy an ice cream cone but rufus was 24 cent short and dufus was 2 cent short of the price of cone. they decided to pool their resources, but found they still could not afford to buy the cone. how many cents did the ice cream cost?
1 solutions

Answer 166086 by ankor@dixie-net.com(15645) About Me  on 2009-10-04 16:20:47 (Show Source):
You can put this solution on YOUR website!
Rus and dufus each took some money from a piggy bank to buy an ice cream cone but rufus was 24 cent short and dufus was 2 cent short of the price of cone. they decided to pool their resources, but found they still could not afford to buy the cone. how many cents did the ice cream cost?
:
Let the cost of the cone = x
then
x - 24 = R's amt
and
x - 2 = D's amt
:
The total amt of both:
(x-24) + (x-2) = (2x - 26)
:
Total amt was not enough to buy a cone, write an inequality
2x - 26 < x
2x - x < 26
x < 26 cents
Let x = 25 cents be the price of a cone
;
Is this true?
25 - 24 = 1 cents for R
and
25 - 2 = 23 cents for D
:
Together they had 24 cents, not enough for a 25 cent cone


Geometry_Word_Problems/221381: A red ball and a green ball are simultaneously tossed in to the air. The red bass is given an initial velocity of 96 feet per second, and its height t seconds after it is tossed is -16^2+96tfeet. The green ball is given an initial velocity of 80 feet persecond, and its height t seconds after it is tossed is -16t^2+80t feet. Find a polynomial d(t) that represents the fiddference in the heights of the two balls, how much higher is the reball 2 seconds after the balls are tossed. In reality, when does the difference in the deights stop increasing?
1 solutions

Answer 166075 by ankor@dixie-net.com(15645) About Me  on 2009-10-04 15:30:07 (Show Source):
You can put this solution on YOUR website!
A red ball and a green ball are tossed into the air. The red ball is given an
initial velocity of 96 feet per second and its height "t" seconds after it is
tossed is -16t^2 + 96t feet.
The green ball is given an initial velocity of 80 feet per second and its height
"t" seconds after being tossed is -16t^2 +80t feet.
:
Find a polynomial D(t) that represents the difference in the heights of the two balls.
D(t) = (-16t^2 + 96t) - (-16t^2 +80t)
:
Remove brackets
D(t) = -16t^2 + 96t + 16t^2 - 80t
:
combine like terms:
D(t) = 16t
:
How much higher is the red ball 2 seconds after the balls are tossed?
D(t) = 16(2)
D(t) = 32 ft difference after 2 seconds
:
When does the difference in the heights stop increasing?
:
Obviously, when one of the balls hits the ground
:
Find when the lowest ball hits the ground (h=0)
-16t^2 + 80t = 0
Factor out -16t
-16t(t - 5) = 0
t = 5 seconds when the difference stops increasing;
:
A graph illustrates this well
+graph%28+300%2C+200%2C+-4%2C+8%2C+-20%2C+150%2C+-16x%5E2%2B96x%2C+-16x%5E2%2B80x%29+


Linear-equations/221070: What would the answer be if i need to write an equation for the line in slope intercept-form when it passes throught (5,-2) and is parallel to y=-9x+6?
1 solutions

Answer 166035 by ankor@dixie-net.com(15645) About Me  on 2009-10-04 11:41:44 (Show Source):
You can put this solution on YOUR website!
What would the answer be if i need to write an equation for the line in slope
intercept-form when it passes through (5,-2) and is parallel to y=-9x+6?
;
remember that parallel lines have the same slope, here it is -9.
:
Use point/slope formula; y - y1 = m(x - x1)
our equation:
y - (-2) = -9(x - 5)
y + 2 = -9x + 45
y = -9x + 45 - 2
y = -9x + 43, is the equation in the slope/intercept form


Circles/221262: I have four circles each with a 10 foot radius, they are put togeather to form a squire of circles what I need to know is the squire foot of the waste in the very middle
1 solutions

Answer 166027 by ankor@dixie-net.com(15645) About Me  on 2009-10-04 11:29:38 (Show Source):
You can put this solution on YOUR website!
I have four circles each with a 10 foot radius, they are put together to form a square of circles.
What I need to know is the square foot of the waste in the very middle.
:
Picture a single circle a radius of 10, inscribed in a single square, a side of 20
Find the area of the square, subtract the area of the circle
:
(20^2) - (pi*10^2) =
400 - 314.159 = 85.84 sq/ft; the total wasted in a all 4 corners
:
This is also the total of the 4 corners from the 4 circles described
therefore
85.84 sq/ft wasted
;
Did this make sense to you?


Numbers_Word_Problems/221245: i am less than 500. i am divisible 11 and 5. i have three digits. the sum of my digits is 14?
1 solutions

Answer 166002 by ankor@dixie-net.com(15645) About Me  on 2009-10-04 09:53:35 (Show Source):
You can put this solution on YOUR website!
i am less than 500. i am divisible 11 and 5. i have three digits. the sum of my digits is 14?
:
with a calc:
multiply 55 * 9 = 495
subtract 55 until the digits add up to 14
440
385
330
275 digits add up to 14