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In a jar there are balls in different colors: blue, red, green and yel [#permalink]
07 Oct 2009, 17:48

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In a jar there are balls in different colors: blue, red, green and yellow. The probability of drawing a blue ball is 1/8. The probability of drawing a red ball is 1/5. The probability of drawing a green ball is 1/10. If a jar cannot contain more than 50 balls, how many yellow balls are in the Jar?

Re: In a jar there are balls in different colors: blue, red, green and yel [#permalink]
07 Oct 2009, 18:30

The answer is A: 23.

First step: determine how many balls are in the jar. Essentially, since the number of balls can't be a decimal number, it must be a multiple of 5, 8 and 10. The LCM of those three numbers is 40.

The probability of drawing a blue ball is 1/8. -> 5 blue balls The probability of drawing a red ball is 1/5. -> 8 red balls The probability of drawing a green ball is 1/10. -> 4 green balls

Re: In a jar there are balls in different colors: blue, red, green and yel [#permalink]
07 Oct 2009, 18:33

mohana wrote:

In a jar there are balls in different colors: blue, red, green and yellow. The probability of drawing a blue ball is 1/8. The probability of drawing a red ball is 1/5. The probability of drawing a green ball is 1/10. If a jar cannot contain more than 50 balls, how many yellow balls are in the Jar?

a) 23. b) 20. c) 24. d) 17. e) 25.

The probability of drawing a blue ball is 1/8 = 5/40 The probability of drawing a red ball is 1/5 = 8/40 The probability of drawing a green ball is 1/10 = 4/40 Yellow balls = 40-(5+8+4) = 23

Re: In a jar there are balls in different colors: blue, red, green and yel [#permalink]
08 Oct 2009, 02:36

LCM of (8,5,10) < 50 ....i.e. 40 balls

The probability of drawing a blue ball is Pb = 1/8 : B/40 thus B = 5 The probability of drawing a red ball is Pr = 1/5 : R/40 thus R = 8 The probability of drawing a green ball is Pg = 1/10 : G/40 thus G = 4

Thus Yellow balls = 40-(5+8+4) = 23....OA A _________________

Bhushan S. If you like my post....Consider it for Kudos

Re: In a jar there are balls in different colors: blue, red, green and yel [#permalink]
03 May 2011, 08:50

total number of balls will have factors 8,5 and 10.Hence the number will be multiple of 40. total balls = 40 yellow ball = 40- (5+8+4) = 23 _________________

Re: In a jar there are balls in different colors: blue, red, green and yel [#permalink]
12 Sep 2014, 12:21

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Re: In a jar there are balls in different colors: blue, red, green and yel [#permalink]
19 Sep 2014, 22:14

mohana wrote:

In a jar there are balls in different colors: blue, red, green and yellow. The probability of drawing a blue ball is 1/8. The probability of drawing a red ball is 1/5. The probability of drawing a green ball is 1/10. If a jar cannot contain more than 50 balls, how many yellow balls are in the Jar?

A. 23 B. 20 C. 24 D. 17 E. 25

# Blue Balls = Total Balls / 8, similarly #Red Balls = TB/5; #Green Balls = TB/10