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 'rfer'

rfer answered: 12640 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, >>Next

real-numbers/315841: what number is 129 less than twice 78?
a boy's step is 1.6dm long. how many steps will it take him to cover 500m distance?
if 12:7=8:n, what is n
the sum of 2 numbers is 76 while the difference is 8. find the smaller number.
1 solutions
Answer 225954 by rfer(12644) About Me  on 2010-06-19 23:23:01 (Show Source):
You can put this solution on YOUR website!
A)
27
B)
500/1.6=312.5 steps
C)
x+x+8=76
2x=68
x=34
x+8=42

Expressions-with-variables/315811: v/R = nT/p solve for R
1 solutions
Answer 225945 by rfer(12644) About Me  on 2010-06-19 21:35:56 (Show Source):

Expressions-with-variables/315766: The expression πr2 gives the area of a circle with radius r. How many square meters of wheat were destroyed when an alien ship made a crop circle of diameter
25 meters in the wheat field at the Southwind Ranch?

1 solutions
Answer 225944 by rfer(12644) About Me  on 2010-06-19 21:34:46 (Show Source):
You can put this solution on YOUR website!
3.14*12.5^2=A
A=490.625 sq meters

Miscellaneous_Word_Problems/315796: A broadway theater has 600 seats, divided into orchestra, main, and balcony seating. Orchestra seats sell for $50, main for $35, and balcony for $25. If all the seats are sold, the gross revenue is $20,800. If all of the main and balcony seats are sold, but only half the orchestra seats are sold, the gross revenue is $17,800. How many are there of each kind of seat?
1 solutions
Answer 225939 by rfer(12644) About Me  on 2010-06-19 21:23:16 (Show Source):
You can put this solution on YOUR website!
6000/50=120 orchestra
m+b=480 b=480-m
35m+25b=14800
35m+25(480-m=14800
35m+12000-25m=14800
10m=2800
m=280 main
balcony = 200

Miscellaneous_Word_Problems/315779: A church seeple casts a shadow 115 ft long, and at the same time a 9.0 ft post cast a shadow 7.0 ft long.How high is the steeple? Round to the nearest unit.
1 solutions
Answer 225921 by rfer(12644) About Me  on 2010-06-19 17:34:49 (Show Source):
You can put this solution on YOUR website!
9/7=x/115
7x=1035
x=148 ft

Proportions/315781: A recipe calls for 2.8 cups of milk for every 6 cups of flour. how much milk would be required for 5.5 cups of flour. write a proportion you would use to solve.
1 solutions
Answer 225919 by rfer(12644) About Me  on 2010-06-19 17:33:00 (Show Source):
You can put this solution on YOUR website!
2.8/6=x/5.5
6x=15.4
x=2.57 cups

Geometry_Word_Problems/315679: perimeter of a rectangle is 112 inches the length exceeds the width by 4 inches find the length and width
1 solutions
Answer 225913 by rfer(12644) About Me  on 2010-06-19 16:35:30 (Show Source):
You can put this solution on YOUR website!
2x+2(x+4)=112
4x+8=112
4x=104
x=26
x+4=30

Miscellaneous_Word_Problems/315714: sum of two numbers is 26. the largest number is 2 less than 3 times the smallest number. what is the smallest number

1 solutions
Answer 225912 by rfer(12644) About Me  on 2010-06-19 16:29:40 (Show Source):
You can put this solution on YOUR website!
x+3x-2=26
4x=28
x=7
3x-2=19

Rectangles/315685: Find the length and the width of a rectangle if the perimeter is 20ft and the length is four time the width.

1 solutions
Answer 225911 by rfer(12644) About Me  on 2010-06-19 16:28:03 (Show Source):
You can put this solution on YOUR website!
2x+2(4x)=20
10x=20
x=2
4x=8

Linear-equations/315763: I need to find the equation when im given the point and slope intercept 0,0 m=2/3
1 solutions
Answer 225909 by rfer(12644) About Me  on 2010-06-19 16:24:51 (Show Source):

Linear-equations/315769: find the slope of the line 3x + 5y = -1
1 solutions
Answer 225908 by rfer(12644) About Me  on 2010-06-19 16:23:16 (Show Source):
You can put this solution on YOUR website!
3x+5y=-1
5y=-3x-1
y=-3/5x-1
m=-3/5

Inequalities/315559: Simplify and graph 6y < 18.

1 solutions
Answer 225815 by rfer(12644) About Me  on 2010-06-18 18:54:25 (Show Source):

Miscellaneous_Word_Problems/315610: Ticket sales. Tickets for a concert were sold to adults for $3 and to students for $2. If the total receipts were $824 and twice as many adult tickets as student tickets were sold, then how many of each were sold?
1 solutions
Answer 225813 by rfer(12644) About Me  on 2010-06-18 18:52:42 (Show Source):
You can put this solution on YOUR website!
3(2x)+2x=824
8x=824
x=103 stdents
2x=206 adults
----------------
3(206)+2*103=824
618+206=824

Travel_Word_Problems/315389: What is the distance traveled at a speed of 60km per hour, for 2hours?
1 solutions
Answer 225662 by rfer(12644) About Me  on 2010-06-17 21:25:00 (Show Source):

Mixture_Word_Problems/315318: A contractor estimated that 30 ft^3 of cement is required to make a concrete floor that measure 90 ft^2. Using this estimate, how much cement is required to make a concrete floor that measures 120ft^2?
1 solutions
Answer 225661 by rfer(12644) About Me  on 2010-06-17 21:24:19 (Show Source):
You can put this solution on YOUR website!
30/90=x/120
90x=3600
x=40 cu ft

Expressions-with-variables/315326: Fun Land theme park has a total of 110 males and females who are employed at the park. If the number of males is 10 more than three times the number of females, how many males are employed at the park?
1 solutions
Answer 225660 by rfer(12644) About Me  on 2010-06-17 21:21:09 (Show Source):
You can put this solution on YOUR website!
3x+10+x=110
4x=100
x=25 females
3x+10=85 males

Expressions-with-variables/315325: x - y = 10
2x + y = 2
SOLVE FOR X&Y
1 solutions
Answer 225659 by rfer(12644) About Me  on 2010-06-17 21:19:07 (Show Source):
You can put this solution on YOUR website!
x-y=10 x=y+10
2x+y=2
2(y+10)+y=2
2y+20+y=2
3y=-18
y=-6
---------------------
2x+-6=2
2x=8
x=4
-----------------
4-(-6)=10

Numeric_Fractions/315351: Six workers worked 14 days and complete 80%of the work. How many days did it take to do the whole job?
1 solutions
Answer 225657 by rfer(12644) About Me  on 2010-06-17 21:14:51 (Show Source):
You can put this solution on YOUR website!
14/.8=17.5 days

Graphs/315354: Give an equation that is slope m=4 and Y intercept of b=-3
1 solutions
Answer 225655 by rfer(12644) About Me  on 2010-06-17 21:13:31 (Show Source):

Expressions-with-variables/315361: How would you write the equation: One added to three times a number is three less than four times the number.
1 solutions
Answer 225654 by rfer(12644) About Me  on 2010-06-17 21:12:38 (Show Source):

test/315368: -8=h/6-3
1 solutions
Answer 225653 by rfer(12644) About Me  on 2010-06-17 21:10:15 (Show Source):
You can put this solution on YOUR website!
-8=h/6-3
-5=h/6
-5/6=h

Coordinate-system/315386: hahhaha ! help me in mathhhhhhhh !
1 solutions
Answer 225651 by rfer(12644) About Me  on 2010-06-17 21:07:23 (Show Source):

Mixture_Word_Problems/315387: John is traveling to a meeting that is 28 miles away. He needs to be there in 30 minutes. How fast does he need to go to make it to the meeting on time?
1 solutions
Answer 225650 by rfer(12644) About Me  on 2010-06-17 21:07:03 (Show Source):

Angles/314990: It measure is 50 less than its supplement?
Its measure is 30 more twice that of its complement?

solve for X
8/12 = x/15


1 solutions
Answer 225398 by rfer(12644) About Me  on 2010-06-16 23:25:16 (Show Source):
You can put this solution on YOUR website!
8/12=x/15
12x=120
x=10

Trigonometry-basics/314997: I have a hypotnuse of 20 and I have an adjacent of 12.The opposite is unknown.I know I have to use cos, but I'm still unsure of how to solve for this.
1 solutions
Answer 225396 by rfer(12644) About Me  on 2010-06-16 23:21:50 (Show Source):
You can put this solution on YOUR website!
c^2-a^2=b^2
400-144=256
sq rt 256=16

Parallelograms/315015: 1- for trapezoid DEFG, T and U are midpoints of the legs. Find TU and m in the problem it is given that


2- The blueprint for a swimming pool is 8 inches by 2 1/2 inches. The actual pool is 136 feet long. Find the width of the pool.



1 solutions
Answer 225393 by rfer(12644) About Me  on 2010-06-16 23:18:28 (Show Source):
You can put this solution on YOUR website!
8/136=2.5/x
8x=340
x=42.5 ft

Evaluation_Word_Problems/315073: An astronaut who weighs 135 pounds on Earth would weigh 35 pounds on the Theta Space Station. If a piece of equipment weighed 2160 pounds on Earth, what would it weigh on Theta Space Station?
1 solutions
Answer 225390 by rfer(12644) About Me  on 2010-06-16 23:12:34 (Show Source):
You can put this solution on YOUR website!
135/35=2160/x
135x=75600
x=560 lbs

Miscellaneous_Word_Problems/315080: A high school graduating class is made of 365 students. There are 111 more girls than boys. How many boys are in the class? Pleas show me step by step the process of the problem.
1 solutions
Answer 225389 by rfer(12644) About Me  on 2010-06-16 23:11:00 (Show Source):
You can put this solution on YOUR website!
x+x+111=365
2x=254
x=127 boys
x+111=238 girls

Rectangles/315083: the length of a rectangle is 4ft longer than twice the width. the perimeter of the rectangle is 56 ft.
draw a rectangle. find its length and width using the perimeter formula. then use the formula to find its area
1 solutions
Answer 225387 by rfer(12644) About Me  on 2010-06-16 23:09:03 (Show Source):
You can put this solution on YOUR website!
2x+2(2x+4)=56
2x+4x+8=56
6x=48
x=8
2x+4=20
-------------
8*20=160 sq ft

Equations/315084: 17-(-8)-4+6 I need to find the solution and know how to work the problem out!
1 solutions
Answer 225382 by rfer(12644) About Me  on 2010-06-16 23:04:52 (Show Source):
You can put this solution on YOUR website!
17-(-8)-4+6
17+8-4+6=27
-----------
look at -(-8)
as -1*-8=+8
- times a - = a plus

Equations/314809: 1/5(x+3)-4=1/2(x+7)
1 solutions
Answer 225248 by rfer(12644) About Me  on 2010-06-16 13:46:56 (Show Source):
You can put this solution on YOUR website!
1/5(x+3)-4=1/2(x+7)
1/5x+1/5*3-4=1/2x+1/2*7
-3/5x+3/5-4=7/2
-3/5x+3/5-20/5=7/2
-3/5x-17/5=7/2
-3/5x=7/2+17/5
-3/5x=35/10+34/10
-3/5x=69/10
x=69/10*-5/3
x=-345/30
x=-11.5 or -11 1/2