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A box has some red and some green balls in it. There are no balls of

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Concentration: Finance, General Management
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A box has some red and some green balls in it. There are no balls of  [#permalink]

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New post 30 Sep 2018, 18:33
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A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

79% (01:12) correct 21% (01:03) wrong based on 24 sessions

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A box has some red and some green balls in it. There are no balls of any other color. Some of these balls are heavy and the rest are all light. What is the probability that a heavy red ball is picked out of the box?

1. The probability of picking a heavy green ball is 20%
2. The probability of picking a light ball is 40%.

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Re: A box has some red and some green balls in it. There are no balls of  [#permalink]

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New post 30 Sep 2018, 19:07
2
For the sake of convenience lets denote,
Light green = lg
Heavy green = hg
Light red = lr
Heavy red = hr
lg+hg+lr+hr = 100 % (say 100 balls)
Implies, lg+hg+lr+hr = 100

From statement 1 we have that the probability of picking up a hg is 20% . That is there are 20 balls which are heavy green out of those 100 balls.
Implies , hg+ lg+ lr+ hr = 100,
Implies, 20+ lg+ lr+ hr = 100,
Implies, lg + lr + hr = 80. But from this equation we do not know the value of heavy red ie hr.
So, insufficient.

Statement 2 says probability of picking a light ball is 40% that is there are 40 balls which are light out of those 100 balls.
So, hg + hr + lr + lg = 100
We have from statement 2, lg + lr = 40
So, hg + hr +40 = 100
Hg+ Hr = 60. Still we cannot find Hr.
So, Insufficient
.
From statement 1 we have , Hg = 20, so, substituting in the result of statement 2, we get , 20 + Hr = 60. Implies Hr = 40.
So the correct option is C.
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Re: A box has some red and some green balls in it. There are no balls of &nbs [#permalink] 30 Sep 2018, 19:07
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A box has some red and some green balls in it. There are no balls of

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