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In box A, there are 10 red marbles, 10 green marbles and 10 yellow mar
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24 Feb 2022, 06:41
24 Feb 2022, 06:41
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Question Stats:
40% (03:13) correct
60% (02:43) wrong based on 5 sessions
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In box A, there are 10 red marbles, 10 green marbles and 10 yellow marbles. Jack takes turn in picking randomly a marble from that box. What is the probability that Jack picks 4 marbles that have the same color?
A. 2/87
B. 16/29
C. 2/261
D. 28/1131
E. 28/3393
A. 2/87
B. 16/29
C. 2/261
D. 28/1131
E. 28/3393
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: In box A, there are 10 red marbles, 10 green marbles and 10 yellow mar
[#permalink]
24 Feb 2022, 06:52
24 Feb 2022, 06:52
Carcass wrote:
In box A, there are 10 red marbles, 10 green marbles and 10 yellow marbles. Jack takes turn in picking randomly a marble from that box. What is the probability that Jack picks 4 marbles that have the same color?
A. 2/87
B. 16/29
C. 2/261
D. 28/1131
E. 28/3393
A. 2/87
B. 16/29
C. 2/261
D. 28/1131
E. 28/3393
P(4 matching marbles) = P(1st is ANY color AND 2nd marble matches 1st AND 3rd marble matches 1st AND 4th marble matches 1st)
= P(1st is ANY color) x P(2nd marble matches 1st) x P(3rd marble matches 1st) x P(4th marble matches 1st)
= 30/30 x 9/29 x 8/28 x 7/27
= 1 x 9/29 x 2/7 x 7/27
= (9)(2)(7)/(29)(7)(27)
= (9)(2)/(29)(27)
= (1)(2)/(29)(3)
= 2/87
Answer: A
gmatclubot
Re: In box A, there are 10 red marbles, 10 green marbles and 10 yellow mar [#permalink]
24 Feb 2022, 06:52
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