Bowl

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Bowl

by goyalsau » Mon Oct 04, 2010 5:12 am
A bowl contains red and green chips and no chips of any other color. If two chips are drawn from the basket at random without replacement, what is the probability that both chips will be green?

1. 20% of all chips in the basket are green.
2. The ratio of the number of red chips to the number of green chips is 4:1.
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by Rahul@gurome » Mon Oct 04, 2010 5:39 am
(1) If total number of chips = 10, then red chips = 8 and green chips = 2
Probability of picking both green chips = 2C2/ 10C2 = 1/45

If total number of chips = 40, then red chips = 32 and green chips = 8
Probability of picking both green chips = 8C2/ 32C2 = 7/124

No unique answer. So, (1) is NOT SUFFICIENT.

(2) Red chips: Green chips = 4:1, which is the same as in statement (1).
So again (2) is NOT SUFFICIENT.

Combining the two statements also doesn't give any further information.

[spoiler]The correct answer is (E).[/spoiler]
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by shovan85 » Mon Oct 04, 2010 5:40 am
IMO E

because either cases we are able to get a propertion of total green chips to total number of chips for the first pick but for second pick there is no information available to us.

Essentially both statements are same.

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by goyalsau » Mon Oct 04, 2010 9:37 am
Rahul@gurome wrote:(1) If total number of chips = 10, then red chips = 8 and green chips = 2
Probability of picking both green chips = 2C2/ 10C2 = 1/45

If total number of chips = 40, then red chips = 32 and green chips = 8
Probability of picking both green chips = 8C2/ 32C2 = 7/124

No unique answer. So, (1) is NOT SUFFICIENT.

(2) Red chips: Green chips = 4:1, which is the same as in statement (1).
So again (2) is NOT SUFFICIENT.

Combining the two statements also doesn't give any further information.

[spoiler]The correct answer is (E).[/spoiler]
Rahul i think should be 40C2 just a small typing mistake,
or it is 32C2
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by Rahul@gurome » Mon Oct 04, 2010 3:10 pm
goyalsau wrote:
Rahul i think should be 40C2 just a small typing mistake,
or it is 32C2
U r right, it should be 40C2. Thanks for catching that!
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