Tutor:

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

---

Recent problems solved by 'rfer'

rfer answered: 12656 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

Mixture_Word_Problems/325039: a man orders 60 pounds of cashews and peanuts, if he orders 24 pounds less of cashews, how many pounds of peanuts was ordered? 1 solutions Answer 232802 by rfer(12660)   on 2010-07-23 20:46:12 (Show Source): You can put this solution on YOUR website! x+x-24=60 2x=84 x=42 x-24=18

Average/325095: His test scores were 80, 88, 71, and 75. After his next test he found his average to be 78. What did he score on his fifth exam? 1 solutions Answer 232799 by rfer(12660)   on 2010-07-23 20:42:02 (Show Source): You can put this solution on YOUR website! (80+88+71+75+x)/5=78 313+x/5=78 313+x=390 x=77

Permutations/325078: If 1.5 chickens lay 1.5 eggs in 1.5 days, how many eggs do 9 chickens lay in 15 days? 1 solutions Answer 232784 by rfer(12660)   on 2010-07-23 18:56:46 (Show Source): You can put this solution on YOUR website! 15*9=135

Linear-equations/325068: How many solutions exist for the following system of equations? -4x – 6y = -28 2x + 3y = 14 And do you know how to enter these type of equations on a graphing calculator? More specific, a TI-84 Plus? 1 solutions Answer 232781 by rfer(12660)   on 2010-07-23 18:14:53 (Show Source): You can put this solution on YOUR website! Enter both equations in the calculator, graph both the intersections of the two are the solution. Refer to web site TI-84 Silver Edition Calculator atomiclearning.com

Money_Word_Problems/325051: $20,000 is invested at 16% per year for 3 months. How much interest is earned on the investment? I've tried 16% divided by 12 = 1 4/12 *3 = 2 1/3 is that right? 1 solutions Answer 232779 by rfer(12660)   on 2010-07-23 18:06:54 (Show Source): You can put this solution on YOUR website! A=20000(1+.16/12)^3 A=20000(1+0.01333)^3 A=20000*1.04 A=20800 20800-20000=$800

Geometric_formulas/324954: what is the length and width of an object that has a perimeter of 42 inches if the width is 5 inches more than the length? 1 solutions Answer 232763 by rfer(12660)   on 2010-07-23 16:44:15 (Show Source): You can put this solution on YOUR website! 2x+2(x+5)=42 4x+10=42 4x=32 x=8 x+5=13

Travel_Word_Problems/324980: Dan and Kathy are both traveling south for spring break. Dan is taking a bus traveling at 60mph and Kathy is driving her own car at 70mph. If Dan passes Jacksonville at 2:00pm and Kathy passes through Jacksonville at 2:30pm what time will Kathy catch up to Dan? 1 solutions Answer 232762 by rfer(12660)   on 2010-07-23 16:41:01 (Show Source): You can put this solution on YOUR website! dan has 30 mi lead overtake at 10 mph 30/10=3 hrs 2:30+3=5:30 pm

Equations/324852: v-4(4-v)=-2(2v-1) 1 solutions Answer 232580 by rfer(12660)   on 2010-07-22 20:16:36 (Show Source): You can put this solution on YOUR website! v-16+4v=-4v+2 9v=18 v=2

Square-cubic-other-roots/324810: if you have a number above the check mark part of the square root what is it called? i am looking for lessons on it but dont know what to look up to find info on it. thanks 1 solutions Answer 232556 by rfer(12660)   on 2010-07-22 19:11:32 (Show Source): You can put this solution on YOUR website! You are referring to the index

Sequences-and-series/324829: What is next in this sequence and how do I solve probems like this, is there a formula? 1 5 14 30 55 91 140 1 solutions Answer 232554 by rfer(12660)   on 2010-07-22 19:04:55 (Show Source): You can put this solution on YOUR website! 204 is next ------------- 1 5 14 30 55 91 140 204 4 9 16 25 36 49 64 5 7 9 11 13 15 2 2 2 2 2

Quadratic_Equations/324725: 5x(x - 1) - 7 = 4x(x -2) 1 solutions Answer 232526 by rfer(12660)   on 2010-07-22 16:40:29 (Show Source): You can put this solution on YOUR website! 5x^2-5x-7=4x^2-8x x^2+3x-7=0

Rectangles/324756: Draw a rectangle with a perimeter of 20 inches label its sides. 1 solutions Answer 232525 by rfer(12660)   on 2010-07-22 16:38:06 (Show Source): You can put this solution on YOUR website! a square with 5 in on each side

test/324794: simplify 2a + 3b - a 1 solutions Answer 232524 by rfer(12660)   on 2010-07-22 16:36:55 (Show Source): You can put this solution on YOUR website! a+3b

Volume/324791: The volume of a cylinder is 1017.88 inches cubed. The radius is 6 inches. WHat is the height? 1 solutions Answer 232522 by rfer(12660)   on 2010-07-22 16:36:30 (Show Source): You can put this solution on YOUR website! 1017.88/3.14*6=h 1017.88/18.84=53.98 in

Expressions-with-variables/324793: Simplify 1.3a + 2b (4b + 3.1a) - 4a 1 solutions Answer 232519 by rfer(12660)   on 2010-07-22 16:34:24 (Show Source): You can put this solution on YOUR website! 1.3a+8b^2+6.2ab-4a +8b^2+6.2ab-2.7a

test/324792: simplify (4x + 3y) - (2x -5y) 1 solutions Answer 232518 by rfer(12660)   on 2010-07-22 16:31:26 (Show Source): You can put this solution on YOUR website! 4x+3y-2x+5y 2x+8y

Graphs/324627: Graph the inequality 2x+4+3x<8+3x+6 1 solutions Answer 232506 by rfer(12660)   on 2010-07-22 16:06:59 (Show Source): You can put this solution on YOUR website! 2x<10 x<5 circle around 5 with arrow pointing to the left

Polynomials-and-rational-expressions/324772: a^2-2-35 with a =1 1 solutions Answer 232504 by rfer(12660)   on 2010-07-22 16:02:10 (Show Source): You can put this solution on YOUR website! a^2-2-35 1^2-2-35 1-2-35=36

Miscellaneous_Word_Problems/324757: a student finishes the first half of an exam in 2/3 the time it takes him to finish the second half. if the entire takes him an hour, how many minutes does he spend on the first half of the exam 1 solutions Answer 232501 by rfer(12660)   on 2010-07-22 16:00:28 (Show Source): You can put this solution on YOUR website! 40 min

percentage/324771: I am taking a practice test. One of my questions is: "A rancher is planning to put up 220 yards of fencing. In the morning, she puts up 80 yards of fencing. In the afternoon she puts up 40% of the remaining fence. What is the total percentage of the amount of fencing she has put up today?" I know the answer is 62%. Every time i work out the answer however, i get 76%. How do you work this problem out? 1 solutions Answer 232498 by rfer(12660)   on 2010-07-22 15:54:58 (Show Source): You can put this solution on YOUR website! 220-80=140 140*.4=56 80+56=136 136/220=0.618or rounded to 62%

Polynomials-and-rational-expressions/324688: Simplify (1/2)^2 and (1/2)^-2 Thank you 1 solutions Answer 232455 by rfer(12660)   on 2010-07-22 13:26:18 (Show Source): You can put this solution on YOUR website! a 1/4 b 4

Polynomials-and-rational-expressions/324737: Simplify 1/z-1 - 1/z+1 1 solutions Answer 232452 by rfer(12660)   on 2010-07-22 13:23:09 (Show Source): You can put this solution on YOUR website! looks like 0

Exponents/324658: I am new at this so here is my problem.-2(5n+5)+6(n-8). I don't understand the order of operations or how to solve. 1 solutions Answer 232444 by rfer(12660)   on 2010-07-22 12:35:42 (Show Source): You can put this solution on YOUR website! remember please excuse my dear aunt sally () x^2 * / + - -2(5n+5)+6(n-8) -10n-10+6n-48 -4n-58

Rectangles/324677: he perimeter of a rectangle is 66cm if the length is twice the width,what are the dimension of the rectangle? 1 solutions Answer 232442 by rfer(12660)   on 2010-07-22 12:29:13 (Show Source): You can put this solution on YOUR website! 2w+2(2w)=66 6w=66 w=11 cm 2w=22 cm

percentage/324712: What is the value of the expression 2x2+3xy-when x=2 and y= -4 1 solutions Answer 232441 by rfer(12660)   on 2010-07-22 12:26:11 (Show Source): You can put this solution on YOUR website! 2*2^2+3*2*-4 8-24=-16

Numeric_Fractions/324592: Simplify (1/4)(-2/7)(5/8)(7/6) 1 solutions Answer 232346 by rfer(12660)   on 2010-07-22 01:19:50 (Show Source): You can put this solution on YOUR website! -2/28*5/8=-10/224 -10/224*7/6=-70/1344=-5/96

Equations/324591: solve 1/3=n/ 4 1/7 1 solutions Answer 232345 by rfer(12660)   on 2010-07-22 01:17:29 (Show Source): You can put this solution on YOUR website! n=1/3*4 1/7 n=1/3*29/7 n=29/21 n=1 8/21

Angles/324497: give the measure of the angle that is complementary to an angle the measures 71 degrees 1 solutions Answer 232256 by rfer(12660)   on 2010-07-21 20:17:03 (Show Source): You can put this solution on YOUR website! 90-71=19 degrees

Polynomials-and-rational-expressions/324467: is 6abcxyz a trinomial a binomial or a monomial? 1 solutions Answer 232231 by rfer(12660)   on 2010-07-21 16:49:48 (Show Source): You can put this solution on YOUR website! monomial, it has just one term

Volume/324457: could you please tell me how many litres would fill a container measuring 9ft x 8ft x 2.5ft 1 solutions Answer 232230 by rfer(12660)   on 2010-07-21 16:47:27 (Show Source): You can put this solution on YOUR website! 9*8*2.5=180 cu ft 180*28.32=5097.6 liters

Linear-equations/324342: determine the present value you must invest to have a future value of $8,500 when the simple interest rate is 7% for 3 years 1 solutions Answer 232226 by rfer(12660)   on 2010-07-21 16:25:15 (Show Source): You can put this solution on YOUR website! A=P(1+r)^n P=A/((1+r)^n) P=8500/((1.07)^3) P=8500/1.225 P=6938.78