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edjones answered: 7568 problems
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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 smaller 1 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=3 1 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 -3 1 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 12 1 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.

Quadratic_Equations/439757: 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+6 1 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 cost 1 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=9 1 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 squared 1 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>100 1 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