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# Recent problems solved by 'checkley77'

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 Probability-and-statistics/251764: a password consists of one letter followed by a six-digit number. how may passwords are possible if ther are no restrictions?1 solutions Answer 183448 by checkley77(12569)   on 2009-12-20 18:27:25 (Show Source): You can put this solution on YOUR website!ONE LETER=26 6 DIGITS=10^6=1,000,000 26*1,000,000=26,000,000 PASSWORDS ARE POSSIBLE.
 Travel_Word_Problems/251775: When Elvis swims with the current, he swims 18km in 2 hours. Against the current, he can swim only 14km in the same time. How fast can Elvis swim in still water and what is the rate of the current?1 solutions Answer 183446 by checkley77(12569)   on 2009-12-20 18:24:07 (Show Source): You can put this solution on YOUR website!D=RT R=D/T R=18/2=9 KMH WITH THE CURRENT. R=14/2=7 KMH AGAINST THE CURRENT. (9-7)/2=2/2=1 KMH IS THE SPEED OF THE CURRENT. PROOF: 9-1=8 SWIMMER'S SPEED. 7+1=8 DITTO.
 Miscellaneous_Word_Problems/251675: A and B, traveling at respective rates of a and b kilometers per hour, head directly towards each other across a distance of 120 kilometers. If both start at 10:30 a.m., they will meet at noon. If A starts at 10:00 a.m. and B starts at 11:00 a.m., they will also meet at noon. Find the ordered pair (a,b). a) (30,30) b) (30,40) c) (40,40) d) (40,30) e) none of these1 solutions Answer 183415 by checkley77(12569)   on 2009-12-20 14:56:05 (Show Source): You can put this solution on YOUR website!D=RT 120=R*1.5 R=120/1.5 R=80 KPH. IS THE COMBINED SPEED OF A&B. 120=RT+(80-R)T 120=R*2+(80-R)1 120=R+80 R=120-80 R=40 80-R=40 ANSWER: C)(40,40)
 Proportions/251718: n-6 n-5 --- = --- 3n 3n+1 1 solutions Answer 183414 by checkley77(12569)   on 2009-12-20 14:43:09 (Show Source): You can put this solution on YOUR website!n-6 n-5 --- = --- 3n 3n+1 cross multiply. 3n(n-5)=(n-6)(3n+1) 3n^2-15n=3n^2-17n-6 3n^3-3n^2-15n+17n=-6 2n=-6 n=-6/2 n=-3 ans. Proof: (-3-6)/-3*3=(-3-5)/(3*-3+1) -9/-9=-8/(-9+1) 1=-8/-8 1=1
 Parallelograms/251719: 3y-8 y ---- = ---- 12 51 solutions Answer 183412 by checkley77(12569)   on 2009-12-20 14:35:53 (Show Source): You can put this solution on YOUR website!3y-8 y ---- = ---- 12 5 cross multiply. 5(3y-8)=12y 15y-40=12y 15y-12y=40 3y=40 y=40/3 ans. Proof: (3*40/3-8)/12=(40/3)/5 (40-8)/12=40/3*1/5 32/12=40/15 32*15=12*40 480=480
 Polynomials-and-rational-expressions/251588: 81m^4-625=1 solutions Answer 183295 by checkley77(12569)   on 2009-12-19 20:21:37 (Show Source): You can put this solution on YOUR website!81m^4-625 (9m^2+25)(9m^2-25) (9m^2+25)(3m+5)(3m-5) ans.
 Linear-systems/251590: i need to solve this word problem with a system of 2 equations. a chemist has one solution containing 20% acid and a second solution containing 30% acid. how many liters of each solution must me combined to obtain 80 liters of a mixture that is 28% acid? i tried the equations L=20a+30b 80L=28(a+b) they didnt work. please help!1 solutions Answer 183294 by checkley77(12569)   on 2009-12-19 20:19:13 (Show Source): You can put this solution on YOUR website!One equation will do the job. .30x+.20(80-x)=.28*80 .30x+16-.20x=22.4 .10x=22.4=-16 .10x=6.4 x=6.4/.10 x=64 liters of 30% solution is used. 80-64=16 liters of 20% solution is used. Proof: .30*64+.20*16=.28*80 19.2+3.2=22.4 22.4=22.4
 Graphs/251594: Graph the equation by plotting points. x = 8 I graphed it on the x axis from 0 to the number 8 on the x axis. I was second guessing myself and thinking I should graph it from 0 to the 8 on the y axis. Which one is right? I would appreciate the help if at all possible. Thanks1 solutions Answer 183291 by checkley77(12569)   on 2009-12-19 20:11:08 (Show Source): You can put this solution on YOUR website!x=8 Is a verticle line through (8,0)
 Volume/251516: What is the height of a cylinder whose surface area is 282.6 square inches and whose radius is 3 inches? 1 solutions Answer 183227 by checkley77(12569)   on 2009-12-19 14:58:29 (Show Source): You can put this solution on YOUR website!A=2PIRH+2PIR^2 282.6=2*3.14*3*H+2*3.14*3^2 282.6=18.84H+56.52 282.6-56.52=18.84H 226.08=18.84H H=226.08/18.84 H=12 INCHES IS THE HEIGHT.
 Inequalities/251539: Determine whether the given numbers are solutions of the inequality 7,-17,-15,-1 y-8>2y-3 is 7 a solution is -17 a solution is -15 a solution is -1 a solution1 solutions Answer 183219 by checkley77(12569)   on 2009-12-19 14:45:31 (Show Source): You can put this solution on YOUR website!7,-17,-15,-1 y-8>2y-3 7-8>2*7-3 -1>14-3 -1>11 --------------- -17-8>2*-17-3 -25>-34-3 -25>-31 -------------------- -15-8>2*-15-3 -23>30-3 -23>-27 ------------------- -1-8>2*-1-3 -9>-2-3 -9>-5 is 7 a solution NO. is -17 a solution YES. is -15 a solution YES. is -1 a solution NO.
 Polynomials-and-rational-expressions/251541: find the least common multiple of 35a^2b^2, 5a^5b^5, 14a^2b^5 1 solutions Answer 183217 by checkley77(12569)   on 2009-12-19 14:40:01 (Show Source): You can put this solution on YOUR website!35a^2b^2, 5a^5b^5, 14a^2b^5 35=1*5*7 5=1*5 14=1*2*7 LCM=1*2*5*7=70 A^2,A^5,A^2=A^5 B^2,B^5,B^5=B^5 70A^5B^5 ans.
 Quadratic_Equations/251319: An open box is to be made from a rectangular piece of tin by cutting two inch squares out of the corners and folding up the sides. The volume of the box will be 100 cubic inches. Find the dimensions of the rectangular piece of tin.1 solutions Answer 183214 by checkley77(12569)   on 2009-12-19 14:26:24 (Show Source): You can put this solution on YOUR website!Let L= the length or the base Let w= the width of the base. AREA=H*LW 100=2*LW LW=100/2 LW=50 ANY SET OF L TIMES W VALUES THAT = 50 ARE ANSWERS FOR THE BASE OF THE BOX. 5*10=50 PROOF: 100=2*5*10 100=100 NOW ADD 4 INCHES TO EACH OF THE BASE MEASUREMENTS FOR THE CORNER CUTS TO FIND THE ORIGINAL SIZE OF THE PIECE OF TIN. (5+4)=9 INCHES (10+4)=14 INCHES THESE COULD BE THE ORIGINAL MEASUREMENTS OF THE TIN.
 Exponential-and-logarithmic-functions/251355: In 1998, the population of a given country was 37 million, and the exponential growth rate was 5% per year. Find the exponential growth function.1 solutions Answer 183209 by checkley77(12569)   on 2009-12-19 13:50:37 (Show Source): You can put this solution on YOUR website!37,000,000(1+.05)^n 37,000,000(1.05)^n where n=the number of years after 1998.
 Polynomials-and-rational-expressions/251444: Multiply and if possible simplify: 8c - 5d^3 ___ ____ d5 10c^51 solutions Answer 183205 by checkley77(12569)   on 2009-12-19 13:45:04 (Show Source): You can put this solution on YOUR website!8c - 5d^3 ___ ____ reduce: 5/10=1/2 d^5 10c^5 (8c/d^5)-(d^3/2c^5) (8c*2c^5-d^3*d^5)/(d^5)(2c^5) (16c^6-d^8)/(d^5)(2c^5) (16c^6-d^8)/(2c^5d^5) ans.
 Polynomials-and-rational-expressions/251445: Divide and simplify (if possible) 15a^5 / 5a^3 _____ ____ 12b^7 3b^21 solutions Answer 183202 by checkley77(12569)   on 2009-12-19 13:31:25 (Show Source): You can put this solution on YOUR website!15a^5 / 5a^3 _____ ____ 12b^7 3b^2 (15a^5/12b^7)*(3b^2/5a^3) 45a^5b^2/60a^3b^7 3a^(5-3)/4b^(7-2) 3a^2/4b^5 ans.
 Polynomials-and-rational-expressions/251446: (y-7)/ 4y^2+21y-49 ___________ y^2-5y-141 solutions Answer 183201 by checkley77(12569)   on 2009-12-19 13:23:54 (Show Source): You can put this solution on YOUR website!(y-7)/ 4y^2+21y-49 ___________ y^2-5y-14 (y-7)/[(4y-7)(y+7)/(y-7)(y+2)] (y-7)
 Travel_Word_Problems/251508: two friends live 525 miles apart. They start driving toward each other at the same time. Jan drives at a speed of 45 mph and Gerry drives at a speed of 60mph. How many hours did it take to meet?1 solutions Answer 183194 by checkley77(12569)   on 2009-12-19 12:49:42 (Show Source): You can put this solution on YOUR website!d=rt 525=(45+60)t 525=105t t=525/105 t=5 hours it will take them to meet. Proof: 525=(45+60)*5 525=105*5 525=252
 Quadratic_Equations/251509: Dr. Taylor can see 10 patients in 5 hours. At this rate, how long would it take him to see 40 patients? 1 solutions Answer 183193 by checkley77(12569)   on 2009-12-19 12:47:17 (Show Source): You can put this solution on YOUR website!10/5=40/x cross multiply 10x=5*40 10x=200 x=200/10 x=20 hours to see 40 patients.
 Quadratic_Equations/251511: x/19 + (2x-4)/191 solutions Answer 183192 by checkley77(12569)   on 2009-12-19 12:45:07 (Show Source): You can put this solution on YOUR website!x/19 + (2x-4)/19 Because the denominators are the same, you can add the numerators. (x+2x-4)/19 (3x-4)/19 ans.
 Percentage-and-ratio-word-problems/251450: Brett took a loan of \$55,000 and paid back a sum of \$58,100 after 2 years. What is the interest he had to pay?1 solutions Answer 183187 by checkley77(12569)   on 2009-12-19 11:02:37 (Show Source): You can put this solution on YOUR website!55,000(1+x)^2=58,100 55,000(1+2x+x^2)=58,100 55,000+110,000x+55,000x^2=58,100 55,000x62+110,000+55,000-58,100=0 55,000x^2+110,000x-3,100=0 1,000(55x^2+110x-3.1)=0 x=(-110+-sqrt[110^2-4*55*-3.1])/2*55 x=(-110+-sqrt12,100+682])/110 x=(-110+-sqrt12,782)/110 x=(-110+-113.0575)/110 x=(-110+113.0575)/110 x=3.0575/110 x=.02779 or 2.779% is the interest rate. Proof: 55,000(1+.02779)^2=58,100 55,000(1.02779)^2=58,100 55,000*1.05635=58,100 58,100~58,100
 Percentage-and-ratio-word-problems/251451: A factory increases the production of cars annually by 5%. If presently it manufactures 370,000 cars per year, how many cars will it manufacture per year after 3 years?1 solutions Answer 183181 by checkley77(12569)   on 2009-12-19 10:47:10 (Show Source): You can put this solution on YOUR website!370,000(1+.05)^3 370,000(1.05)^3 370,000*1.1576=\$428,321 ans.
 Polynomials-and-rational-expressions/251459: (6x^3/2y^2)/(4x^7/5y^4)1 solutions Answer 183179 by checkley77(12569)   on 2009-12-19 10:42:45 (Show Source): You can put this solution on YOUR website!(6x^3/2y^2)/(4x^7/5y^4) (6x^3/2y^2)*(5y^4/4x^7) (30x^3y^4)/(8x^7y^2) 15y^2/4x^4 ans.
 Percentage-and-ratio-word-problems/251454: A company has plans to increase its sales at the rate of 10% per year. If the sales of the company in 2001 were \$ 37 million, how much sales can you expect the company to make in the year 2004?1 solutions Answer 183178 by checkley77(12569)   on 2009-12-19 10:37:27 (Show Source): You can put this solution on YOUR website!37,000,000(1+.10)^3 37,000,000(1.1)^3 37,000,000*1.33=\$49,247,000 is the expected sales in 2004.
 Polynomials-and-rational-expressions/251456: 70x^2y^4/40x^3y1 solutions Answer 183177 by checkley77(12569)   on 2009-12-19 10:33:31 (Show Source): You can put this solution on YOUR website!70x^2y^4/40x^3y 70/40=7/4 x^2/x^3=1/x y^4/y=y^3 7/4*1/x*y^3 7*1*y^3/4*x 7y^3/4x ans.
 Polynomials-and-rational-expressions/251457: (10/b^2)*(4/25b^4)1 solutions Answer 183174 by checkley77(12569)   on 2009-12-19 10:29:12 (Show Source): You can put this solution on YOUR website!(10/b^2)*(4/25b^4) 40/25b^6 8/5b^6 ans.
 Polynomials-and-rational-expressions/251462: ((y^2-9)/y^3))/((y^6-3y^5)/(y-5))1 solutions Answer 183173 by checkley77(12569)   on 2009-12-19 10:26:30 (Show Source): You can put this solution on YOUR website!((y^2-9)/y^3))/((y^6-3y^5)/(y-5)) [(y+3)(y-3)/y^3]/[y^5(Y-3)/(Y-5)] [(Y+3)(Y-3)/Y^3] CANCEL OUT THE (Y-3) TERMS & THE Y^3 TERMS. [(Y+3)] (Y+3)(Y-5)/Y^2 ANS.
 Miscellaneous_Word_Problems/251471: The perimeter of one square is 3 times the perimeter of another square. The area of the larger square is how many times the area of the smaller square ? (A) 2 (B) 3 (C) 4 (D) 91 solutions Answer 183168 by checkley77(12569)   on 2009-12-19 10:08:49 (Show Source): You can put this solution on YOUR website!Let x be the side of the smaller square 4x=perimeter. Area=x^2 4*3x=12x is this perimeter 12x/4=3x is the length of the sides. area=(3x)^2 9x^2 is this area. Amswer D).
 Travel_Word_Problems/251472: If you walk for 45 minutes at a rate of 4 mph and then run for 30 minutes at a rate of 10 mph, how many miles have gone at the end of one hour and 15 minutes ? (A) 3.5 miles (B) 8 miles (C) 9 miles (D) 25 1/3 miles1 solutions Answer 183166 by checkley77(12569)   on 2009-12-19 10:00:44 (Show Source): You can put this solution on YOUR website!3/4*15+1/2*40 45/4+40/2 11.25+20=31.25 miles is the distance traveled.
 Graphs/251493: in the problem -x - y < 3 how do you get the y to be positive? when put in y = mx + b form for graphing linear inequalities1 solutions Answer 183163 by checkley77(12569)   on 2009-12-19 09:55:44 (Show Source): You can put this solution on YOUR website!-x - y < 3 -y < x+3 now divide all terms by -1. y > -x-3 [note: when dividing by a negative value the < sign changes to a > sign]. (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, -x -3).
 Evaluation_Word_Problems/251439: The Everton College paid \$1862 for an order of 48 calculators. The store paid \$11 for each scientific calculator The others all graphing calculators cost the store \$57 each how many of each type of calculator was ordered? The store ordered ____ scientific and _____ graphing calculators.1 solutions Answer 183130 by checkley77(12569)   on 2009-12-18 22:05:06 (Show Source): You can put this solution on YOUR website!11s+57g=1,862 s+g=48 or s=48-g replace s with (48-g) in the equation above & solve for g. 11(48-g)+57g=1,862 528-11g+57g=1,862 46g=1,862-528 46g=1,334 g=1,334/46 g=29 graphing calculators were bought. 48-29=19 scientific calculators were bought. Proof: 11*19+57*29=1,862 209+1,653=1,862 1,862=1,862
 decimal-numbers/251221: 0.5x=6.5 0.04y=5.2 1 solutions Answer 183129 by checkley77(12569)   on 2009-12-18 21:51:16 (Show Source): You can put this solution on YOUR website!0.5x=6.5 x=6.5/.5 x=13 ans. Proof: .5*13=6.5 6.5=6.5 -------------- 0.04y=5.2 y=5.2/.04 y=130 ans. Proof: .04*130=5.2 5.2=5.2