Discussion of Question with ID = 021 under Probability

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Question

A bag contains 2 Red, 8 Blue and 4 Green marbles. What is the probability of drawing a Red marble if 2 marbles are drawn out randomly?

A

${25/91}$.

B

$4/14$.

C

$26/91$.

D

$30/91$.

Soln.
Ans: a

Total number of marbles is 14. Combinations of 2 marbles that are possible = 14C2 = ${14 × 13}/2$ = 91. If one of the two balls is red, then red + red is one possibility, and 2 × (8 + 4) are the other possibilities. So total favorable outcomes = 1 + 2 × 12 = 25, and the probability is 25/91 = ${25/91}$.


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