Discussion of Question with ID = 049 under Probability

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Question

A box contains 6 cyan, 3 pink and 8 orange marbles. What is the probability of drawing a orange marble if 2 marbles are drawn out randomly?

A

\${25/34}\$.

B

\$8/17\$.

C

\$26/136\$.

D

\$30/136\$.

Soln.
Ans: a

Total number of marbles is 17. Combinations of 2 marbles that are possible = 17C2 = \${17 × 16}/2\$ = 136. If one of the two balls is orange, then both balls will be orange in 8C2 = \${8 × (8 - 1)}/2\$ = 28 ways. The number of ways in which non-orange can be drawn out are 8 × (6 + 3). So total favorable outcomes = 28 + 8 × 9 = 100, and the probability is 100/136 = \${25/34}\$.