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A jar contains 12 marbles consisting of an equal number of red, green,
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20 Oct 2021, 09:17
20 Oct 2021, 09:17
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Question Stats:
58% (02:48) correct
41% (01:38) wrong based on 12 sessions
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A jar contains 12 marbles consisting of an equal number of red, green, and blue marbles. Four marbles are removed from the jar and discarded. What is the probability that only two colors will remain in the jar after the four marbles have been removed?
(A) 1/495
(B) 1/165
(C) 1/81
(D) 1/3
(E) 1/2
(A) 1/495
(B) 1/165
(C) 1/81
(D) 1/3
(E) 1/2
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Re: A jar contains 12 marbles consisting of an equal number of red, green,
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20 Oct 2021, 09:43
20 Oct 2021, 09:43
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Carcass wrote:
A jar contains 12 marbles consisting of an equal number of red, green, and blue marbles. Four marbles are removed from the jar and discarded. What is the probability that only two colors will remain in the jar after the four marbles have been removed?
(A) 1/495
(B) 1/165
(C) 1/81
(D) 1/3
(E) 1/2
(A) 1/495
(B) 1/165
(C) 1/81
(D) 1/3
(E) 1/2
We're starting with: R, R, R, R, G, G, G, G, B, B, B, B
So, P(only 2 colors remaining) = P(all 4 selected marbles are the SAME color)
P(all 4 selected marbles are the SAME color) = P(1st marble is ANY color AND 2nd marble matches 1st marble AND 3rd marble matches 1st marble AND 4th marble matches 1st marble)
= P(1st marble is ANY color) x P(2nd marble matches 1st marble) x P(3rd marble matches 1st marble) x P(4th marble matches 1st marble)
= 1 x 3/11 x 2/10 x 1/9
= 1/165
Answer: B
Re: A jar contains 12 marbles consisting of an equal number of red, green,
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04 Dec 2023, 20:19
04 Dec 2023, 20:19
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