Question

A fair dice is thrown 3 times.The probability that the product of 3 outcomes is a prime number is

• A. 1/24
• B. 1/36
• C. 1/32
• D. 1/8

Answer 1

The correct option is A 1/24

The product is prime only when outcomes is (1, 1, 3) or (1, 1, 5) or (1, 1, 2) in all other cases it will be even.

1, 1, 3 can occur in 3 ways similarly for (1, 1, 2) and (1, 1, 5).

Favourable = 9

Total ways: 216

P= $\frac{9}{216}$ = $\frac{1}{24}$