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There are red, yellow, and blue marbles in a bag of 50 marbles. If Mar

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Bunuel
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There are red, yellow, and blue marbles in a bag of 50 marbles. If Mar [#permalink] New post   07 Apr 2016, 08:41
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There are red, yellow, and blue marbles in a bag of 50 marbles. If Mark selects two marbles from the bag, and then Omar selects one marble, how many blue marbles are left in the bag before Omar selects his marble?

(1) After two marbles are selected, the probability of Omar selecting a red marble with one pick is 6/24.
(2) After two marbles are selected, the probability of Omar selecting a blue marble with one pick is 3/4.
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chetan2u
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Re: There are red, yellow, and blue marbles in a bag of 50 marbles. If Mar [#permalink] New post   07 Apr 2016, 20:56
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Bunuel wrote:
There are red, yellow, and blue marbles in a bag of 50 marbles. If Mark selects two marbles from the bag, and then Omar selects one marble, how many blue marbles are left in the bag before Omar selects his marble?

(1) After two marbles are selected, the probability of Omar selecting a red marble with one pick is 6/24.
(2) After two marbles are selected, the probability of Omar selecting a blue marble with one pick is 3/4.


HI,
total marbles = 50..
after mark picks up two, remaining are 48..

lets see the statements



(1) After two marbles are selected, the probability of Omar selecting a red marble with one pick is 6/24.
6/24 = 12/48, which gives us the number of red marbles in 48, NOTHING about BLUE..
Insuff

(2) After two marbles are selected, the probability of Omar selecting a blue marble with one pick is 3/4.
\(\frac{3}{4} = \frac{3*12}{4*12}= \frac{36}{48}\)..
so there are total 36 blue marble in 48
suff
B
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Re: There are red, yellow, and blue marbles in a bag of 50 marbles. If Mar [#permalink] New post   13 Apr 2016, 10:23
i stumbled upon 36/48... and choose B.was not sure till I saw the first answer by chetan2u
probably a stupid question,but can we say that there were 38 blue balls in the bag originally???
Can you please answer this ... If not then how do we find it out ....????
Can you help chetan2u???
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Re: There are red, yellow, and blue marbles in a bag of 50 marbles. If Mar [#permalink] New post   13 Apr 2016, 11:45
nikhiljd wrote:
i stumbled upon 36/48... and choose B.was not sure till I saw the first answer by chetan
probably a stupid question,but can we say that there were 38 blue balls in the bag originally???
Can you please answer this ... If not then how do we find it out ....????
Can you helpchetan???


We can't say how many blue balls were in the bag originally. Both (1) and (2) give only information about the probabilities AFTER the first two were picked. Therefore we don't know anything about which colors these were. But it also doesn't matter because this is not what was asked!
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Re: There are red, yellow, and blue marbles in a bag of 50 marbles. If Mar [#permalink] New post   21 Jul 2020, 06:26
Hello from the GMAT Club BumpBot!

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Re: There are red, yellow, and blue marbles in a bag of 50 marbles. If Mar [#permalink]
21 Jul 2020, 06:26
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