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Recent problems solved by 'edjones'

edjones answered: 7568 problems
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Probability-and-statistics/479413: 45. A national pollster has developed 15 questions designed to rate the performance of the president of the United States. The pollster will select 10 of these questions. How many different arrangements are there for the order of the 10 selected questions? 1 solutions Answer 328503 by edjones(7569)   on 2011-08-08 20:19:48 (Show Source): You can put this solution on YOUR website! Since arrangements are required this is a permutation. nPr=15P10=15!/(15-10)! =15!/5! =10897286400 arrangements . Ed

Probability-and-statistics/479410: The Pizza Shop wanted to determine what proportion of its customers ordered only cheese pizza. Out of 80 customers surveyed, 15 ordered cheese pizza. What is the 99% confidence interval of the true proportion of customers who order only cheese pizza? 1 solutions Answer 328502 by edjones(7569)   on 2011-08-08 20:15:03 (Show Source): You can put this solution on YOUR website! p=15/80=.1875, q=.8125, (a,b)=.1875 +-(2.576*.0436) [2.576 is the area under the normal curve for the 99% confidence level.] =.1875 +-.1123 =(.2998, .0752) the 99% confidence interval of the true proportion of customers who order only cheese pizza.

Probability-and-statistics/479389: six people were asked to determine the amount of money they were carrying, to the nearest dollar. the result were 18, 49, 41, 45, 24, and 34. 1 solutions Answer 328490 by edjones(7569)   on 2011-08-08 19:26:35 (Show Source): You can put this solution on YOUR website! What is the question.

Probability-and-statistics/479416: Find each probability, each item is replaced: A box contains 10 red, 4 blue and 4 white marbles. Choose a blue, then a red marble 1 solutions Answer 328489 by edjones(7569)   on 2011-08-08 19:25:15 (Show Source): You can put this solution on YOUR website! 10+4+4=18 4/18 * 10/18 =2/9 * 5/9 =10/81 . Ed

Polynomials-and-rational-expressions/479360: The reciprocal of a number plus the reciprocal of twice the number equals 3/10 Find the number. please 1 solutions Answer 328473 by edjones(7569)   on 2011-08-08 18:23:28 (Show Source): You can put this solution on YOUR website! 1/x + 1/2x = 3/10 10+5=3x 3x=15 x=5 . Ed

test/479362: 1.If 3x-11/2=5x^0,what is the value of x? 2.If 2x^-1=5/3,what is the value of x? 3.If k/x-1x^2=k,what is the value of x when k=4? Please help and thank you so much.I really appreciate for giving your time to help solve these problems.Thanks again. 1 solutions Answer 328471 by edjones(7569)   on 2011-08-08 18:20:38 (Show Source): You can put this solution on YOUR website! 2) 2x^-1=5/3 2/x=5/3 6=5x x=6/5 . Ed

Average/479364: On a school test, The average score for the girls in the class is 91, and the average score for the boys in the class is 85. If the average score for the class is 89, what fraction of the class are boys? I should resolve it by a system... 91x + 85y= 89 (x+y) But then?? Thanks in advance. 1 solutions Answer 328465 by edjones(7569)   on 2011-08-08 18:14:45 (Show Source): You can put this solution on YOUR website! (91x+85y)/(x+y)=89 91x + 85y= 89 (x+y) ...=89x+89y 2x=4y y=x/2 1/3 of the class are boys. . Ed

Triangles/479370: what is the length of the diagonal of a square with side lengths 7 square root of 2 1 solutions Answer 328459 by edjones(7569)   on 2011-08-08 17:59:40 (Show Source): You can put this solution on YOUR website! a^2+b^2=c^2 2(7sqrt(2))^2 =2*49*2 =196 c=14 the length of the diagonal. . Ed

Age_Word_Problems/479371: The ages of a mother and daughter add up to 66. The Mother's age is the daughter's age reversed. How old could they be? 1 solutions Answer 328458 by edjones(7569)   on 2011-08-08 17:54:32 (Show Source): You can put this solution on YOUR website! m+d=66 d=10t+u m=10u+t 10t+u+10u+t=66 llu+11t=66 u+t=6 . 24 and 42 or 15 and 51 or 06 and 60 (unlikely) . Ed

Proportions/479378: What is your mile time if you ran a mile and a half in 14 minutes? 1 solutions Answer 328449 by edjones(7569)   on 2011-08-08 17:35:30 (Show Source): You can put this solution on YOUR website! x/1=14/1.5 x=28/3 min . Ed

Numbers_Word_Problems/479381: if i am 2 digit and my ones is three times my tens digit,what numbers can i be? 1 solutions Answer 328446 by edjones(7569)   on 2011-08-08 17:31:15 (Show Source): You can put this solution on YOUR website! tu u=3t t+3t 13, 26 or 39 . Ed

Exponential-and-logarithmic-functions/479374: Solve 4^5x = 66. Round to the nearest ten-thousandths. 1 solutions Answer 328445 by edjones(7569)   on 2011-08-08 17:27:10 (Show Source): You can put this solution on YOUR website! 4^5x = 66 log[4](5x)=log[4]66 5x=3.0222 x=.6044 . Ed

Sequences-and-series/479376: Please help. Simplify by removing factors of 1. p^2-9 ______ (p+3)^2 1 solutions Answer 328441 by edjones(7569)   on 2011-08-08 17:15:32 (Show Source): You can put this solution on YOUR website! (p^2-9)/(p+3)^2 =((p+3)(p-3))/(p+3)^2 (p-3)/(p+3) . Ed

Probability-and-statistics/475616: You have measured the percentage of days your company met production targets across two sites. At one site, you measure 80 days and found that the site missed the production goals 11 times. At site two, you measured 92 days and found that the site missed the production goals 10 times. At the 90% confidence level, can you say that site two missed the production goal fewer times than site one? State your hypothesis: 1 solutions Answer 326161 by edjones(7569)   on 2011-07-28 22:22:26 (Show Source): You can put this solution on YOUR website! H[o]: site two missed the production goal fewer times than site one. Site #1: p=11/80=.1375, q=1-.1375=.8625, n=80 Site #2: p=10/92=.1087, q=1-.1087=.8913, n=92 =.0385+.0325=.071 z=(.1375-.1087)/.071=.4056 Using a single tailed test z=.4056 has an area of .3245 under the normal curve and the null hypothesis is not confirmed. . Ed

Equations/475500: Please show me the steps to perform the following multiplication problem. Thanks. 2√5(√11+√5) 1 solutions Answer 326150 by edjones(7569)   on 2011-07-28 21:40:51 (Show Source): You can put this solution on YOUR website! 2√5(√11+√5) =2sqrt(55)+2sqrt(25) =10+2sqrt(55) . Ed

Geometric_formulas/475545: A single die is rolled one time. Determine the probability of rolling a number greater than 3 or less than 5. 1 solutions Answer 326146 by edjones(7569)   on 2011-07-28 21:31:41 (Show Source): You can put this solution on YOUR website! greater than 3: 3/6=1/2 less than 5: 4/6=2/3

Evaluation_Word_Problems/475567: when 60 is increased by 60% it then is equal to what number decreased by 60%? 1 solutions Answer 326144 by edjones(7569)   on 2011-07-28 21:27:48 (Show Source): You can put this solution on YOUR website! 60*+60*.6=x-.6x 96=.4x x=240 . Ed

Evaluation_Word_Problems/475568: Please help....Solve and graph x2 + x – 4 = 0. (x^2+x-4 =0) Please list the steps, Thanks ! 1 solutions Answer 326141 by edjones(7569)   on 2011-07-28 21:22:06 (Show Source): You can put this solution on YOUR website! x^2+x-4=0 . Solved by pluggable solver: SOLVE quadratic equation with variable Quadratic equation (in our case ) has the following solutons: For these solutions to exist, the discriminant should not be a negative number. First, we need to compute the discriminant : . Discriminant d=17 is greater than zero. That means that there are two solutions: . Quadratic expression can be factored: Again, the answer is: 1.56155281280883, -2.56155281280883. Here's your graph: . Ed

Probability-and-statistics/475573: 40(0.6)+30(0.4)-3 find the mean 1 solutions Answer 326139 by edjones(7569)   on 2011-07-28 21:17:43 (Show Source): You can put this solution on YOUR website! 40(0.6)+30(0.4)-3 =24+12-3 =33 33/3=11 the mean

Systems-of-equations/475588: The difference of two numbers is 2 and the sum of thier squares is 52 1 solutions Answer 326136 by edjones(7569)   on 2011-07-28 21:12:06 (Show Source): You can put this solution on YOUR website! x-y=2 x^2+y^2=52 . x=y+2 (y+2)^2+y^2=52 y^2+4y+4+y^2=52 2y^2+4y-48=0 y^2+2y-24=0 (y+6)(y-4)=0 y=-6, x=-4 or y=4, x=6 . Ed

Square-cubic-other-roots/475593: rationalize the denominator square root fratction √(r- √s) /√(r+ √s) =1 is the denominator rationalized is this correct? 1 solutions Answer 326132 by edjones(7569)   on 2011-07-28 21:03:02 (Show Source): You can put this solution on YOUR website! √(r- √s) /√(r+ √s) =1 r-sqrt(s)/r+sqrt(s)=1 square each side. r-sqrt(s)=r+sqrt(s) Therefore s must equal zero and r can be any number. . Ed

Sequences-and-series/475598: what is the fourth term in this sequence: A(n)=5*(-3)^n-1 1 solutions Answer 326131 by edjones(7569)   on 2011-07-28 20:49:49 (Show Source): You can put this solution on YOUR website! A(n)=5*(-3)^(n-1) A(4)=5*(-3)^3 =5*-27 =-135 . Ed

Signed-numbers/474224: Solve. x^2 +14x = -49 1 solutions Answer 325251 by edjones(7569)   on 2011-07-25 16:51:42 (Show Source): You can put this solution on YOUR website! x^2 +14x = -49 x^2+14x+49=0 (x+7)^2=0 x=-7 . Ed

Signed-numbers/474223: solve by factoring 6x^2 -21x -12= 0 1 solutions Answer 325249 by edjones(7569)   on 2011-07-25 16:47:40 (Show Source): You can put this solution on YOUR website! 6x^2 -21x -12= 0 6*-12=-72, Two factors of -72 whose sum is -21 are -24 and +3 6x^2+3x-24x-12=0 3x(2x+1)-12(2x+1)=0 (3x-12)(2x+1)=0 3x=12, 2x=-1 x=4, x=-1/2 . Ed

Signed-numbers/474208: (3y-5)^2 1 solutions Answer 325246 by edjones(7569)   on 2011-07-25 16:41:33 (Show Source): You can put this solution on YOUR website! (3y-5)^2 =(3y-5)(3y-5) F 9y^2 O -15y I -15y L 25 --------add 9y^2-30y+25 . Ed

Radicals/474221: solve for z, write your answer in the simplest form 1+(8/z)=(5/3) 1 solutions Answer 325244 by edjones(7569)   on 2011-07-25 16:36:26 (Show Source): You can put this solution on YOUR website! 1+(8/z)=(5/3) 3z+24=5z multiply each side by 3z 2z=24 z=12 . Ed

Probability-and-statistics/474194: A slot machine is configured so that there is a 1/2000 probability of winning the jackpot on any individual trial. Suppose a guest claims that she played the slot machine 5 times and hit the jackpot twice. Find the probability of exactly 2 jackpots in 5 trials. find the probability of at least 2 jackpots in 5 trials. does the guest's claim of hitting 2 jackpots in 5 trials seem valid? 1 solutions Answer 325241 by edjones(7569)   on 2011-07-25 16:31:03 (Show Source): You can put this solution on YOUR website! p=1/2000, q=1999/2000, n=5 nCr=5C2=10 coefficient 10p^2*q^3 =.0000025 . Ed

Probability-and-statistics/474198: Which of the following statistics are unbiased estimators of population parameters? a. sample mean used to estimate a population mean b. sample median used to estimate a population median c. sample range used to estimate a population range 1 solutions Answer 325236 by edjones(7569)   on 2011-07-25 16:15:36 (Show Source): You can put this solution on YOUR website! a and b

Probability-and-statistics/474201: Mars Inc, claims 24% of M&M plain candies are blue. Suppose that a sample of 100 M&Ms are randomly selected and 27 are found to be blue. Assuming the claimed blue M&Ms rate of 24% is correct, find the probility of randomly selecting 100 M&Ms and getting 27 or more that are blue. Based on your result, is 27 an unusually high number of blue M&Ms when 100 are randomly selected? 1 solutions Answer 325226 by edjones(7569)   on 2011-07-25 16:02:15 (Show Source): You can put this solution on YOUR website! p=24, q=.76, n=100 z=(27.5-24)/4.48=3.5/4.48=.781 area under normal curve above z=.781 is .217 the probility of randomly selecting 100 M&Ms and getting 27 or more that are blue. It is not an unusually high result. . Ed

Square-cubic-other-roots/474117: 3sqrt(23)x7sqrt(10) 8sqrt(32)+3sqrt(2) 6sqrt(3)/3sqrt(81) -2sqrt2x-2sqrt7 1 solutions Answer 325208 by edjones(7569)   on 2011-07-25 15:21:29 (Show Source): You can put this solution on YOUR website! 8sqrt(32)+3sqrt(2) =8sqrt(16*2)+3sqrt(2) =32sqrt(2)+3sqrt(2) =35sqrt(2) . Ed

Probability-and-statistics/474151: between z= -1.56 and z=-1.83 to the right of z = -0.18 to the left of z= 2.16 to the right of z = 1.98 and to the left of z= -0.59 1 solutions Answer 325204 by edjones(7569)   on 2011-07-25 15:15:14 (Show Source): You can put this solution on YOUR website! between z= -1.56 and z=-1.83 .907