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# Recent problems solved by 'edjones'

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 Probability-and-statistics/440530: One thousand raffle tickets are sold for \$5.00 each. One grand prize of \$1000 and two consolation prizes of \$100 each will be awarded. Jeremy purchases one ticket. Find his expected value.1 solutions Answer 304294 by edjones(7569)   on 2011-04-25 20:26:42 (Show Source): You can put this solution on YOUR website!1000+100+100=\$1200. 1200/1000=\$1.20 the expected value of his ticket. . Ed
 Polynomials-and-rational-expressions/440526: My name is John, I am in 8th grade, and I would like some help with these two problems below. I don't quiet understand how to find the common factor for grouped binominals. here are the problems: 1.: (xa+xb) + (5xa+5xb) 2: (4ac+7ad) + (42cd-24cb) Thank you already for your help. I really appreciate it! 1 solutions Answer 304290 by edjones(7569)   on 2011-04-25 20:12:08 (Show Source): You can put this solution on YOUR website!1: xa + xb 5xa+5xb -------- 6xa+6xb . Ed
 Surface-area/440519: so there are two squares, one inside the other. the outside one is 10 by 10ft, and you want a tile border around the edges. Each tile in the border is exactly 1 by 1ft. Please help me with an algebric way to calculate the border area, if this was bigger or smaller1 solutions Answer 304288 by edjones(7569)   on 2011-04-25 20:07:20 (Show Source): You can put this solution on YOUR website!The inside square is 8' by 8'. Let b=boarder area b=10^2-8^2 =100-64 =36 ft^2 . Ed
 Probability-and-statistics/440511: a bag contains 10 marbles (4 red, 2 white and 4 blue). if you select 3 marbles at random from the bag without replacement, what is the probability ( as a common fraction) that exactly two of the marbles selected will be red? Plz help me fast this problem is killing me!1 solutions Answer 304282 by edjones(7569)   on 2011-04-25 19:59:17 (Show Source): You can put this solution on YOUR website!nCr=Combination of n things taken r at a time ((4C2)(6C1))/10C3 Combination of 4 red balls taken 2 at a time times one of the six other balls, all divided by the combination of 10 balls take 3 at a time. =(6*6)/120 =36/120 =3/10 . Ed
 testmodule/440503: what number should be added to both sides of the equation to complete the square x^2+10x=31 solutions Answer 304277 by edjones(7569)   on 2011-04-25 19:51:21 (Show Source): You can put this solution on YOUR website!25 Answer How to do it. Divide the coefficient of x by 2 and square the result and add it to each side. . Ed
 Equations/440501: I am having trouble with this equation Solve by clearing fractions; 2/7 + x = x/3 -31 solutions Answer 304276 by edjones(7569)   on 2011-04-25 19:46:27 (Show Source): You can put this solution on YOUR website!2/7 + x = x/3 -3 6+21x=7x-63 multiply each side by 21 (LCM). 14x=-69 x=-69/14 . Ed
 Geometry_Word_Problems/440496: One card is selected at random from a deck of cards. Determine the probability that the card is a 3 or 7.1 solutions Answer 304273 by edjones(7569)   on 2011-04-25 19:40:16 (Show Source): You can put this solution on YOUR website!A standard deck has 52 cards. There are 4 threes and 4 sevens. 4+4=8 8/52=2/13 the probability that the card is a 3 or 7. . Ed
 Numbers_Word_Problems/440487: In a kennel, a cocker spaniel, a bulldog, and a greyhound all give birth to litters.The number of pups in the litters are consecutive integers (in the order: cocker spaniel, bulldog, greyhound.) The first integer increased by twice the second exceeds the third by 10. How many puppies does each dog have? Use the 5 step method.1 solutions Answer 304270 by edjones(7569)   on 2011-04-25 19:37:14 (Show Source): You can put this solution on YOUR website!Let the integers be x, x+1, and x+2 x+2(x+1)=x+2+10 x+2x+2=x+12 3x+2=x+12 2x=10 x=5 . Cocker 5 Bulldog 6 Greyhound 7 . Ed
 Probability-and-statistics/440489: The theoretical probability of undesirable side effects resulting from taking Grebex is 1 in 20. If 100 people take Grebex to lower their blood pressure, how many will encounter undesirable side effects?1 solutions Answer 304267 by edjones(7569)   on 2011-04-25 19:27:08 (Show Source): You can put this solution on YOUR website!100 * 1/20 = 5
 Quadratic_Equations/440466: A perimeter of a rectangle is 8 meters and its area is 3.84 m. What are the dimensions?1 solutions Answer 304266 by edjones(7569)   on 2011-04-25 19:25:03 (Show Source): You can put this solution on YOUR website!2L+2w=P 2L+2w=8 L+w=4 L=4-w . Lw=A Lw=3.84 w(4-w)=3.84 4w-w^2=3.84 w^2-4w=-3.84 multiply each side by -1. w^2-4w+4=4-3.84 completing the square. (w-2)^2=.16 w-2=+-.4 w=1.6m, L=2.4m . Ed
 Equations/440468: How do you solve the following equation: 2x squared minus 5x equals 121 solutions Answer 304263 by edjones(7569)   on 2011-04-25 19:10:41 (Show Source): You can put this solution on YOUR website!2x^2-5x=12 2x^2-5x-12=0 2*-12=-24; The two factors of -24 whose sum is -5 are -8 and +3. 2x^2+3x-8x-12=0 x(2x+3)-4(2x+3)=0 (x-4)(2x+3)=0 x=4, 2x=-3, x=-3/2 . Ed
 Rate-of-work-word-problems/440455: How many workers will be needed to complete a task in 3 days, given that it takes 10 days for 6 workers to complete the same task?1 solutions Answer 304260 by edjones(7569)   on 2011-04-25 18:57:24 (Show Source): You can put this solution on YOUR website!It takes 10*6=60 worker-days to do the job. 60/3=20 workers are necessary to do the work in 3 days. . Ed
 Probability-and-statistics/439766: A certain type of machine requires repairs once every two years on average. What is the probability that such a machine will work at least two years without requiring repair? A company has four such machines which operate independently. What is the probability that at least one of them will not need repair in the next 2 years?1 solutions Answer 303933 by edjones(7569)   on 2011-04-24 11:02:07 (Show Source): You can put this solution on YOUR website!1/2 the probability that such a machine will work at least two years without requiring repair. (1/2)^4=1/16 probability all will need repair in the next 2 years. 1 - 1/16 = 15/16 the probability that at least one of them will not need repair in the next 2 years. . Ed
 Evaluation_Word_Problems/439760: how many pounds of peanuts costing \$2.00 a pound should be mixed with 4 pounds of cashews costing \$4.50 a pound to obtain a mixture costing \$3.00 a pound?1 solutions Answer 303931 by edjones(7569)   on 2011-04-24 10:47:35 (Show Source): You can put this solution on YOUR website!let p = pounds of peanuts. (2p+4.5*4)/(p+4) = 3 (2p+18)/(p+4) = 3 2p+18=3p+12 -p=-6 p=6 lbs.
1 solutions

Answer 303929 by edjones(7569)   on 2011-04-24 10:33:46 (Show Source):
You can put this solution on YOUR website!
4k(k+5)=5
4k^2+20k=5
4k^2+20k-5=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=480 is greater than zero. That means that there are two solutions: . Quadratic expression can be factored: Again, the answer is: 0.238612787525831, -5.23861278752583. Here's your graph:

.
Ed

 test/439762: 15x=13x+61 solutions Answer 303928 by edjones(7569)   on 2011-04-24 10:25:28 (Show Source): You can put this solution on YOUR website!15x=13x+6 2x=6 subtract 13x from each side. x=3 divide each side by 2. . Ed
 Probability-and-statistics/439682: During the first half of the NBA season, the LA lakers won half of their games. What percentage of the remaining half must win to increase the winning by 55%1 solutions Answer 303926 by edjones(7569)   on 2011-04-24 10:20:23 (Show Source): You can put this solution on YOUR website!Let's pretend that the Lakers played 200 games in the 1st 1/2 of the season and that they won 100 and lost 100. To raise their winning pct by 55% they would have to win 155 games and lose 45. 155/200=.775 percentage of the remaining half must win to increase the winning by 55%. . Ed
 Permutations/439727: 1.in how many ways can the letters of the word WORLD be arranged such that O and R may always be together? 1 solutions Answer 303923 by edjones(7569)   on 2011-04-24 10:07:34 (Show Source): You can put this solution on YOUR website!4!=4*3*2=24 24*2=48 ways (O and R can be together as OR or RO.) . Ed
 Permutations/439731: 1. a baseball team has 3 catchers, 9 pitchers, 6 infielders, and 7 outfielders. In how many ways can a team of 9 be chosen for a game? 2.how many poker hands consist of 3 aces and 2 kings? 3.from a group of 6 representatives of labor, 5 representatives of business, 8 representatives of the general public, how many commitees of 6 can be formed consisting of 2 people from each group? 4. In how many ways can be eleven chosen out of batch of 15 players? how many of these will: A) include one particular player? B) exclude one particular player?1 solutions Answer 303922 by edjones(7569)   on 2011-04-24 10:00:06 (Show Source): You can put this solution on YOUR website!nCr=Combination of n things taken r at a time=n!/((n-r)!*r!) 1. On a baseball team there is 1 pitcher, 1 catcher, 4 infielders and 3 outfielders. 3*9*6C4*7C3 =27*15*35 =14,175 ways . Ed
 Money_Word_Problems/439735: a shopkeeper sells his all item at 40% above costs. if he allows a special discount of 15% to hos friends on selling price. compute his profit as a percentage of cost1 solutions Answer 303920 by edjones(7569)   on 2011-04-24 09:51:22 (Show Source): You can put this solution on YOUR website!Let c=cost c+.4c=1.4c price of items 1.4c*.85=1.19c price of items to friends 119% profit as a percent of cost. . Ed
 Rational-functions/439741: Consider the function defined by f(x)=sqrt(x-2)-1 a. use algebra to verify that the function is one-to-one. b. sketch the graphs of f and f^-1 on the same coordinate axes. Label each graph. This area of PreCal is foreign to me and I am in need of help. I would appreciate any help I receive. Thank you.1 solutions Answer 303918 by edjones(7569)   on 2011-04-24 09:40:26 (Show Source): You can put this solution on YOUR website!Some functions do not have inverses. If a function never takes on the same value twice, then it has inverse. You can tell if a function has an inverse by drawing a horizontal line across its graph. If no horizontal line intersects its graph more than once then it has a one to one relationship and has and inverse. In the graphs below the top ((x+2)^2-1) fails the horizontal line test and does not have an inverse. The bottom ((x+2)^3-1) has an inverse because it passes the horizontal line test. For every value of x there is only one value of y. It is one to one. . Ed . .
 Probability-and-statistics/439750: What is the probability that a 31 day month will have 5 Mondays. Assume that there is an equal chance of any one of the seven days being the first day of the month. Show all working.1 solutions Answer 303915 by edjones(7569)   on 2011-04-24 09:36:17 (Show Source): You can put this solution on YOUR website!Any 31 day month whose 1st day is a Saturday, Sunday or Monday has 5 Mondays. 3/7 of 31 day months begin with those 3 days. 3/7 is the probability that a 31 day month will have 5 Mondays. . Ed
 Inverses/439738: Question: Verify that the function f(x)=(x+2)^2-1 is not one-to-one. I do not understand this problem at all. The term one-to-one is unclear to me. Please help with solving. Thank you.1 solutions Answer 303914 by edjones(7569)   on 2011-04-24 09:30:40 (Show Source): You can put this solution on YOUR website!Some functions do not have inverses. If a function never takes on the same value twice, then it has inverse. You can tell if a function has an inverse by drawing a horizontal line across its graph. If no horizontal line intersects its graph more than once then it has a one to one relationship and has and inverse. In the graphs below the top ((x+2)^2-1) fails the horizontal line test and does not have an inverse. The bottom ((x+2)^3-1) has an inverse because it passes the horizontal line test. For every value of x there is only one value of y. It is one to one. . Ed . .
 Square-cubic-other-roots/439285: solve and check 12+square root of x+5=91 solutions Answer 303667 by edjones(7569)   on 2011-04-22 22:46:08 (Show Source): You can put this solution on YOUR website!12+sqrt(x+5)=9 sqrt(x+5)=-3 x+5=9 square each side x=4 . Since 3<>-3 there is no answer. . Ed
 test/439290: I have to simplfy some problems that contain letters and exponets the problem is 6x^4•x^2 , what's the answer?1 solutions Answer 303665 by edjones(7569)   on 2011-04-22 22:39:52 (Show Source): You can put this solution on YOUR website!6x^4•x^2 =6x^6 add the exponents.
 Square-cubic-other-roots/439359: what is 10 squared1 solutions Answer 303662 by edjones(7569)   on 2011-04-22 22:34:16 (Show Source): You can put this solution on YOUR website!10*10=100
 Numbers_Word_Problems/439377: the sum of the digits is 5 their difference is 3 the number is odd.1 solutions Answer 303661 by edjones(7569)   on 2011-04-22 22:32:01 (Show Source): You can put this solution on YOUR website!x+y=5 x-y=3 ------add 2x=8 . x=4 y=1 . 41 is the number . Ed
 Radicals/439380: I need help with solving a radical eguation including a root: sqrt(x)-1=sqrt(5+sqrt(x)) Thank you! 1 solutions Answer 303660 by edjones(7569)   on 2011-04-22 22:28:23 (Show Source): You can put this solution on YOUR website!sqrt(x)-1=sqrt(5+sqrt(x)) x-2sqrt(x)+1=5+sqrt(x) square each side. x-4=3sqrt(x) x^2-8x+16=9x square each side x^2-17x+16=0 (x-16)(x-1)=0 x=16 . Ed
 Miscellaneous_Word_Problems/439387: A custom printing shop is planning on adding Painter's caps to it's product line. For the first year, the fixed cost for setting up production are \$30,000. The variable cost for producing a dozen caps are \$10. The revenue on each dozen caps will be \$25. Total profit P(x)= \$15 I need the break even point expressed as follows: (?,?)1 solutions Answer 303645 by edjones(7569)   on 2011-04-22 21:55:37 (Show Source): You can put this solution on YOUR website!30000/15=2000 2000*12=24,000 The sale of 24,000 caps will be the break even point. . Ed
 Inequalities/439394: -25t>1001 solutions Answer 303641 by edjones(7569)   on 2011-04-22 21:43:22 (Show Source): You can put this solution on YOUR website!-25t>100 t<-4 Reverse the inequality sign when dividing by a negative number. . Ed
 Equations/439395: Solve the equations. Show all work. 1.√(2x-9)=3 2. 3x^3-4x^2-27x+36=0 3. |2x-1|=7 4.√(2x-3)=x-3 5.3y^4+4y^2-4=0 6.8x-22x^1/2-21=0 1 solutions Answer 303638 by edjones(7569)   on 2011-04-22 21:39:43 (Show Source): You can put this solution on YOUR website!1. √(2x-9)=3 2x-9=9 2x=18 x=9 . Ed