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# Recent problems solved by 'edjones'

edjones answered: 7568 problems
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 Probability-and-statistics/579317: On New Years eve, The probability of driving while intoxicated is .32 The probability of having a driving accident is .09 What is the probability of a person having a driving accident while intoxicated?1 solutions Answer 370937 by edjones(7569)   on 2012-02-28 04:24:18 (Show Source): You can put this solution on YOUR website!Since the chance of having an accident while driving intoxicated are greatly increased the probability cannot be calculated from the statistics given.
 Probability-and-statistics/579316: if three people are randomly selected, what is the probability at least two of them have the same birthday?1 solutions Answer 370936 by edjones(7569)   on 2012-02-28 04:16:03 (Show Source): You can put this solution on YOUR website!Eliminate leap year for simplicity. (365/365)*(364/365)*(363/365)=.9918 probability that none have the same birthday. 1-.9918=.0082 the probability that at least two of them have the same birthday. . Ed
 Miscellaneous_Word_Problems/579299: If John gives Allen \$5 and Allen gives Frank \$2, the 3 boys will have the same amount of money. How much more money does John have than Allen? A) \$3 B) \$5 C) \$6 D) \$7 E) \$8 It seems like a simple problem but I don't know how to solve it.. Thanks!1 solutions Answer 370934 by edjones(7569)   on 2012-02-28 03:44:38 (Show Source): You can put this solution on YOUR website!J-5=A+3 not A+5 because after A+5 Allen gives 2 away. J=A+8 E
 Miscellaneous_Word_Problems/579305: Chris has twice as many baseball cards as Lee. If Chris gives Lee 10 of his baseball cards, he will have half as many as Lee. How many baseball caards do Chris and Lee have together? A) 10 B) 20 C) 30 D) 40 E) 60 I'm not sure how to approach this and solve it.. Thanks!1 solutions Answer 370933 by edjones(7569)   on 2012-02-28 03:33:49 (Show Source): You can put this solution on YOUR website!C=2L C-10=L+10 . C=L+20 2L=L+20 L=20 C=40 L+C=60 E . Ed
 Permutations/579306: How many ways can you order a pizza if you choose 1 vegatable, 1 meat, and 1 cheese. Options are Vegatable= 8 Meat=7 Cheese=31 solutions Answer 370932 by edjones(7569)   on 2012-02-28 03:28:33 (Show Source): You can put this solution on YOUR website!8*7*3=168 ways
 Mixture_Word_Problems/579166: You have 5M sodium acetate (MW=82.03) solution and need 25mls of a 1.5M solution. How much of the original solution should you use? I said (x)(5M)=(25mls)(1.5M) which is 37.5 mls..is this correct?1 solutions Answer 370892 by edjones(7569)   on 2012-02-27 21:03:22 (Show Source): You can put this solution on YOUR website!(x)(5M)=(25ml)(1.5M) x=(25*1.5)/5 =7.5 ml . Ed
 Polynomials-and-rational-expressions/579159: 9+6k-8k^21 solutions Answer 370889 by edjones(7569)   on 2012-02-27 20:55:16 (Show Source): You can put this solution on YOUR website!9+6k-8k^2 =-8k^2+6k+9 -8*9=-72; +12 and -6 are factors of -72 whose sum is +6. -8k^2+12k-6k+9 =-4k(2k-3)-3(2k-3) Factoring by grouping = -(4k+3)(2k-3) . Ed
 Parallelograms/579147: The measure of one interior angle of a parallelogram is 0.25 times the measure of another angle. Find the measure of each angle.1 solutions Answer 370885 by edjones(7569)   on 2012-02-27 20:42:35 (Show Source): You can put this solution on YOUR website!Let the larger angle be a. 2a+2*.25a=360 2a+.5a=360 2.5a=360 a=144 deg .25a=36 deg . Ed
 Probability-and-statistics/579098: The average hourly wage of plumbers is normally distributed with a population mean of \$32.00 and a population standard deviation of \$6.00. Calculate the following: (a) The proportion of plumbers earning between \$20 and \$24. (b) The proportion of plumbers earning more than \$38. (c) The proportion of plumbers earning less than \$15. (d) Calculated the 80th percentile.1 solutions Answer 370880 by edjones(7569)   on 2012-02-27 20:29:35 (Show Source): You can put this solution on YOUR website!a) z=(20-32)/6=-12/6=-2 z=(24-32)/6=-8/6=-4/3 Area under normal curve between -2 and -4/3 is .068 The proportion of plumbers earning between \$20 and \$24. . Ed
 Permutations/579112: How many ways can a president and vice president be selected in a class of fifteen students?1 solutions Answer 370877 by edjones(7569)   on 2012-02-27 20:19:35 (Show Source): You can put this solution on YOUR website!15P2 =15!/(15-2)! =15!/13! =(15*14*13!)/13! =15*14 =210 ways . Ed
 Radicals/579122: Can you please help me with the below algebra problem. f(x)= sqrt (4x-16)1 solutions Answer 370875 by edjones(7569)   on 2012-02-27 20:16:37 (Show Source): You can put this solution on YOUR website!f(x)= sqrt (4x-16) =2sqrt(x-4) . Ed
 Numeric_Fractions/579131: Two numbers have a ratio of 12 to 7. Their sum is 95. Find the number of the smaller value1 solutions Answer 370871 by edjones(7569)   on 2012-02-27 20:12:11 (Show Source): You can put this solution on YOUR website!12+7=19 95/19=5 5*7=35 the number of the smaller value. . Ed
 Travel_Word_Problems/578845: If Dennis rides his bike at a speed of 12 mi/h, how far will he ride in 3 hours1 solutions Answer 370800 by edjones(7569)   on 2012-02-27 13:29:09 (Show Source): You can put this solution on YOUR website!rt=d 12*3=36 mi
 Mixture_Word_Problems/578847: 2x+5=11 solutions Answer 370798 by edjones(7569)   on 2012-02-27 13:27:23 (Show Source): You can put this solution on YOUR website!2x+5=1 2x=-4 subtract 5 from each side. x=-2 divide each side by 2. . Ed
 percentage/578819: 90% of 24 is what1 solutions Answer 370796 by edjones(7569)   on 2012-02-27 13:25:28 (Show Source): You can put this solution on YOUR website!24*.9=21.6
 Divisibility_and_Prime_Numbers/578828: I have three factors. the sum of my factors is 7. What am I?1 solutions Answer 370795 by edjones(7569)   on 2012-02-27 13:22:03 (Show Source): You can put this solution on YOUR website!12 factors are 2, 2, 3
 Money_Word_Problems/578736: Peg works 2 1/2 hours each day on 4 days a week sewing covers. At \$11.25 per hour, how much does she earn each week?1 solutions Answer 370760 by edjones(7569)   on 2012-02-27 10:25:56 (Show Source): You can put this solution on YOUR website!2.5*4*11.25=\$112.50
Equations/578740: X{X-5}=8+(X-3)

1 solutions

Answer 370757 by edjones(7569)   on 2012-02-27 10:23:04 (Show Source):
You can put this solution on YOUR website!
X{X-5}=8+(X-3)
x^2-5x=8+x-3
x^2-6x-5=0
x=3-sqrt(14), x=3+sqrt(14) (see below)
.
Ed
.
 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=56 is greater than zero. That means that there are two solutions: . Quadratic expression can be factored: Again, the answer is: 6.74165738677394, -0.741657386773941. Here's your graph:

 Expressions-with-variables/558804: y/(5y+3) = 1/(2y) solve1 solutions Answer 363200 by edjones(7569)   on 2012-01-17 23:44:04 (Show Source): You can put this solution on YOUR website!y/(5y+3) = 1/(2y) y(2y)=5y+3 2y^2-5y-3=0 2y^2-6y+y-3=0 2y(y-3)+1(y-3)=0 (2y+1)(y-3)=0 y=3, y=-1/2 . Ed
 Coordinate-system/558188: We are trying to figure out how to solve the question- we don't want the answer just the steps needed to proceed. Find the slope of each line and tell whether the lines are parallel, perpendicular, or neither y=3x+1 y=3x-31 solutions Answer 362944 by edjones(7569)   on 2012-01-16 20:33:11 (Show Source): You can put this solution on YOUR website!The slope of both is 3 (the number before the x) so they are parallel.
 logarithm/558183: How do i write this as a single logarithm:ln (x/x-1)+ln (x+1/x)-ln (x^2-1)1 solutions Answer 362941 by edjones(7569)   on 2012-01-16 20:29:58 (Show Source): You can put this solution on YOUR website!ln(x/(x-1))+ln((x+1)/x)-ln(x^2-1) = = =
 Percentage-and-ratio-word-problems/558174: Mrs.Redmon and Mrs. Browder bought 4 1/8 cups of soda to share. Mrs.Redmon drank 2 1/3 cups of the soda. How much did Mrs.Browder drank?1 solutions Answer 362933 by edjones(7569)   on 2012-01-16 20:04:34 (Show Source): You can put this solution on YOUR website!4 1/8 = 33/8 = 99/24 2 1/3 = 7/3 = 56/24 . 99/24 - 56/24 = 43/24 cups . Ed
 Sequences-and-series/558170: I'm working with fraction exponents i.e. #roots. I know how to solve for the variable when it is an exponent, but this is a new lesson where I have to solve for the variable that is a base. This what I've tried, but I've hit a dead end. Problem: Step 1: or is it ---I got same bases on both sides of the equation and had 4^(3-24) subsitute my value for 40, since (4^3)=64, but I would have to subtract 24 from either the exponent or from the whole side of the equation. Here's where I hit a wall and I don't know what to do after that since I tried to do both of my alternatives. P.S. This is an excercise to get our feet wet for tomorrow's lesson.1 solutions Answer 362929 by edjones(7569)   on 2012-01-16 19:58:45 (Show Source): You can put this solution on YOUR website!16d^(1/4)=40 d^(1/4)=5/2 d=(5/2)^4=625/16 Take each side to the 4th power. . Ed
 Triangles/558159: a 30-60-90 triangle with hypotenuse length 28 centimeters. what is the perimeter and area of the triangle?1 solutions Answer 362927 by edjones(7569)   on 2012-01-16 19:48:06 (Show Source): You can put this solution on YOUR website!c=28 cm The sides are in a ratio of 1:2:sqrt(3) 14:28:14sqrt(3) =14:28:24.2 =14+28+24.2=66.2 cm perimeter. A=ab/2 =14^2 =196 cm^2 . Ed
 Probability-and-statistics/558141: For a certain game, the probability of choosing a card with the number 13 is .008. What is the probability of not choosing card 13?1 solutions Answer 362923 by edjones(7569)   on 2012-01-16 19:35:45 (Show Source): You can put this solution on YOUR website!1-.008=.992 the probability of not choosing card 13.
 Proportions/558152: if y=45 when x=9, find y when x=7 solve. 1 solutions Answer 362921 by edjones(7569)   on 2012-01-16 19:30:06 (Show Source): You can put this solution on YOUR website!y/7=45/9 y=35 . Ed
 Permutations/555554: I feel as though i know the answer. i have followed the formula but i dont think i understand. please help... A group of 5 candidates are running for 2 different class offices. In how many ways can the offices be filled by these candidates? .... i was wondering if it was 20 ways because i know the formula is nPr= n! over r!(n-r)! .... so i just was wondering if i was right.1 solutions Answer 361831 by edjones(7569)   on 2012-01-11 00:05:23 (Show Source): You can put this solution on YOUR website!The formula you gave above is incorrect. So how did you get the correct answer? 5P2=5!/(5-2)! =5!/3! =5*4*3!/3! =20 ways . Ed
 Rectangles/555482: the perimeter of a rectangle is 114 feet. its length is three more than twice its width. can you help me solve this please ? 1 solutions Answer 361830 by edjones(7569)   on 2012-01-10 23:55:11 (Show Source): You can put this solution on YOUR website!2L+2w=114 L=2w+3 . 2(2w+3)+2w=114 4w+6+2w=114 6w=108 w=18' L=39' . Ed
 Exponents-negative-and-fractional/555490: Please help me solve this equation: 2xy^4/5xy^2 x -30xy/2x^2y 1 solutions Answer 361828 by edjones(7569)   on 2012-01-10 23:48:42 (Show Source): You can put this solution on YOUR website!2xy^4/5xy^2 x -30xy/2x^(2)y =2y^2/5 - 15/x =(2xy^2-75)/5x . Ed
 Triangles/555492: What is the height of an equilateral triangle with sides of 10 in long 1 solutions Answer 361827 by edjones(7569)   on 2012-01-10 23:39:58 (Show Source): You can put this solution on YOUR website!The altitude divides the triangle into 2 right triangles, each with a hypotenuse of 10" and a base of 5". a^2+b^2=c^2 a^2+5^2=10^2 a^2+25=100 a^2=75 a=sqrt(75) =sqrt(25*3) =5sqrt(3)" the height . Ed
 expressions/555493: (x squared + 5y) squared1 solutions Answer 361824 by edjones(7569)   on 2012-01-10 23:32:59 (Show Source): You can put this solution on YOUR website!(x^2+5y)^2 =x^4+10x^2y+25y^2 . Ed