New!
Get regular updates about newly solved problems
via algebra.com's RSS system.
Recent problems solved by 'Fombitz'
Fombitz answered: 13805 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, >>NextEquations/343460: an aircraft flies 120 km south, then 150 km east, then 200 km north. how far is the aircraft its starting position????? 1 solutions
Answer 245774 by Fombitz(13828) on 2010-09-15 13:27:26 (Show Source):
You can put this solution on YOUR website!Let the starting point be the origin (0,0).
Let east be positive x, west negative x.
Let north be positive y, south negative y.
.
.
.
Starting at (0,0)
120km south: (0,0)+(0,-120)=(0,-120)
150 km east:(0,-120)+(150,0)=(150,-120)
200 km north: (150,-120)+(0,200)=(150,80)
The aircraft's currently 150 east and 80 miles north of the starting point.
.
.
.
Use the distance formula to find the distance.
 km
|
Probability-and-statistics/343363: The question is to determine the area under the standard normal curve that lies either to the left of -2.12 or to the right of 1.67.
So, this is what I came up with:
0.0170+(1-9525) =-9523
I know the answer is 0.0645, but I cannot determine how to come up with that answer. Can you help me? Thank you for any help you can give me. 1 solutions
Answer 245771 by Fombitz(13828) on 2010-09-15 13:20:43 (Show Source):
|
Angles/343331: The sum of the measures of two complementary angles is 90 degrees. If one angle measures 15 degrees more than twice the measure of its complement , find the measure of each angle. How do I figure out what numbers to use? 1 solutions
Answer 245741 by Fombitz(13828) on 2010-09-15 11:16:14 (Show Source):
You can put this solution on YOUR website!You need to solve 2 equations simultaneously.
First name the variables.
Let  be the angle.
Let  be the complement.
1.  By definition.
That's the first equation.
Then also,
2.
Now you can substitute eq. 2 into eq. 1 and solve for  .
.
.
.
 degrees
Then from eq. 1,
 degrees
|
Expressions-with-variables/343293: I'm not sure if this is the right category but it seems correct. Example: 9x = 3x
Find the value of X. I need an explanation on how to do one like the one mentioned before, and one like this: 4x (+ or -) 15 = 30. Also, 4x (+ or -) 6 = 25x. These are just examples I made up, none of them are actual questions. I just need help on the steps to solve it. 1 solutions
Answer 245728 by Fombitz(13828) on 2010-09-15 10:21:28 (Show Source):
You can put this solution on YOUR website!When you have an equation, you can add or subtract, multiply and divide, by any number as long as you do it to both sides of the equation (except division by zero).
You want to isolate all the x terms on one side, all the constant terms on the other.
Eventually you want an equation that looks like, x=...., because then you're done, you've solved the problem.
Here's an example.

Add  to both sides, to remove it from the right hand side.

Subtract  from both sides, to remove it from the left hand side.

Divide both sides by  .

You're done, you've solve for x.
You can verify the solution by plugging it into your original equation.

Multiply both sides by 3 to eliminate the fractions.

True, so the solution is valid.
.
.
.
Not all equations have a solution.

Subtract  from both sides.

That's obviously not true, so no x solves that problem.
There is no solution.
.
.
.
Here are your two examples without all of the steps.
Make sure you understand how to go from 1 step to the next.

.
.
.

.
.
.
Good luck.
|
Numbers_Word_Problems/343289: A mechanic has two antifreeze solutions. One is 70% antinfreeze and the other is 40% antifreeze. How much of each solution should be mixed to make 60 gallons of a solution that is 52% antifreeze? 1 solutions
Answer 245706 by Fombitz(13828) on 2010-09-15 09:02:18 (Show Source):
You can put this solution on YOUR website!Let A be the amount of 70% antinfreeze, B the amount of 40% antifreeze.
1. 
.
.
.

2. 
From eq. 1,

Substitute into eq. 2,
 gallons
Then from eq. 1,
 gallons
|
Triangles/343272: Is it possible for four lines in a plane to have exactly zero points of intersection? One point? Two points? Three points? Four points? Five points? Six points? Draw a figure to support each of your answer. 1 solutions
Answer 245704 by Fombitz(13828) on 2010-09-15 08:56:08 (Show Source):
|
Probability-and-statistics/343352: please help me solve
what is a family's probability of having two boys and two girls, if it has four children? 1 solutions
Answer 245701 by Fombitz(13828) on 2010-09-15 08:43:05 (Show Source):
You can put this solution on YOUR website!Look at the possible outcomes of the children in order of birth.
There are  or  total outcomes.
1.B B B B
2.B B B G
3.B B G B
4.B B G G
5.B G B B
6.B G B G
7.B G G B
8.B G G G
9.G B B B
10.G B B G
11.G B G B
12.G B G G
13.G G B B
14.G G B G
15.G G G B
16.G G G G
Look at the outcomes that have two boys and two girls.
There are 6 of them (4,6,7,10,11,13).
|
Probability-and-statistics/343357: Three fair coins are tossed. What is the probability that at least two are heads?
Please help solve 1 solutions
Answer 245697 by Fombitz(13828) on 2010-09-15 08:36:39 (Show Source):
You can put this solution on YOUR website!Look at the possible outcomes.
There are 8 of them.
H H H
H H T
H T H
H T T
T H H
T H T
T T H
T T T
Count the ones that have at least 2 heads.
There are four of them.
The probability is then 4 possible outcomes out of 8 total outcomes.
|
Linear-equations/343313: explain how to determine if an ordered pair is the solution to a system of linear equations. Give an example and explanation. 1 solutions
Answer 245634 by Fombitz(13828) on 2010-09-14 23:00:59 (Show Source):
You can put this solution on YOUR website!Plug the ordered pair into the equation.
If it satisfies the equation, it is a solution.
If it doesn't, it's not.

Try (2,11)

False, (2,11) is not a solution.
.
.
.
Try (-2,1)

True, (-2,1) is a solution.
|
|