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A jar contains only B black marbles, W white marbles, a

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A jar contains only B black marbles, W white marbles, a

by varun289 » Sat Dec 15, 2012 10:23 am
290. A jar contains only B black marbles, W white marbles, and R red marbles. If one marble is to be chosen at random from a jar, is the probability that the marble chosen will be red greater than the probability that the marble chosen will be white?
1) r / (b + w) > w / (b + r)
2) b-w > r
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Source: — Data Sufficiency |
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by puneetkhurana2000 » Sat Dec 15, 2012 11:06 am
We have to find is r > b ?

Statement 1 ) Cross multiply we get rb + r^2 > wb + w^2

Further solving we get (r - w)(r+w+b) > 0

As r+w+b is > 0 , so for inequality to hold true (r - w) > 0 , hence r > w. Sufficient!!!

Statement 2 ) (b - w) > r or b > w + r , so w > r or r > w or w = r . Not Sufficient!!!

Answer A .
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