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A bag has 20 marbles that are either black or white.

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Carcass
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A bag has 20 marbles that are either black or white. [#permalink] New post   25 Dec 2018, 15:14
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A bag has 20 marbles that are either black or white.

Quantity A
Quantity B
The number of times one must randomly draw a marble from the bag, without replacing it, to ensure that at least 4 black marbles are selected
The number of times one must randomly draw a marble from the bag, without replacing it, to ensure that at least 4 white marbles are selected


A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.
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D
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Fatemeh
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Re: A bag has 20 marbles that are either black or white. [#permalink] New post   26 Dec 2018, 13:12
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Answer: D
20 marbles: black or white
A: The number of times one must randomly draw a marble from the bag, without replacing it, to ensure that at least 4 black marbles are selected

B: The number of times one must randomly draw a marble from the bag, without replacing it, to ensure that at least 4 white marbles are selected

Since we don’t have any information about the number of black or white ones, we can't decide which one is more or less, therefore, we can't construe about their probabilities. hence, the answer is D.
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Re: A bag has 20 marbles that are either black or white. [#permalink] New post   27 Dec 2018, 00:25
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Carcass wrote:
A bag has 20 marbles that are either black or white.

Quantity A
Quantity B
The number of times one must randomly draw a marble from the bag, without replacing it, to ensure that at least 4 black marbles are selected
The number of times one must randomly draw a marble from the bag, without replacing it, to ensure that at least 4 white marbles are selected


A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.


Our answer will be the marbles which are lesser than the other.
Say there are 5 black and 15 whites..
We can be sure that 4 whites are there if we pick 5+4=9 and that 4 blacks are there if we pick 15+4=19..

But we are not aware of the number of black or white marbles.

Thus D
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Re: A bag has 20 marbles that are either black or white. [#permalink] New post   09 Sep 2019, 19:21
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Carcass wrote:

This question is part of GREPrepClub - The Questions Vault Project



A bag has 20 marbles that are either black or white.

Quantity A
Quantity B
The number of times one must randomly draw a marble from the bag, without replacing it, to ensure that at least 4 black marbles are selected
The number of times one must randomly draw a marble from the bag, without replacing it, to ensure that at least 4 white marbles are selected


A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.


We don't know what's in the bag. EX. what if they're all white or all black?

Since we already found 2 answers that that would change the answer, clearly we don't have a enough information.

D.
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Re: A bag has 20 marbles that are either black or white. [#permalink] New post   23 Feb 2023, 07:30
Hello from the GRE Prep Club BumpBot!

Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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Re: A bag has 20 marbles that are either black or white. [#permalink]
23 Feb 2023, 07:30
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