Question

Two dice are tossed. The probability that the total score is a prime number is

Options

• `1/6`

• `5/12`

• `1/2`

• `7/9`

Answer 1

`5/12`
Explanation:
Clearly, n(S) = (6 x 6) = 36
Let E = Event that a sum is a prime number.
Then E = {(1, 1), (1, 2), (1, 4), (1, 6), (2, 1), (2, 3), (2, 5), (3, 2), (3, 4), (4, 1), (4, 3), (5, 2), (5, 6), (6, 1), (6, 5)}
Now, n(E) = 15

∴ P E = `(n(E))/(n(S))`

= `15/36=5/12`