Question

Two different dice are thrown together. Find the probability that the numbers obtained have a sum less than 7.

In a simultaneous throw of a pair of dice, find the probability of getting a sum less than 7.

Answer 1

The outcomes when two dice are thrown together are

(1,1), (1,2), (1,3), (1,4), (1,5), (1,6)

(2,1), (2,2), (2,3), (2,4), (2,5), (2,6)

(3,1), (3,2), (3,3), (3,4), (3,5), (3,6)

(4,1), (4,2), (4,3), (4,4), (4,5), (4,6)

(5,1), (5,2), (5,3), (5,4), (5,5), (5,6)

(6,1), (6,2), (6,3), (6,4), (6,5), (6,6)

Total number of outcomes = 36

Let A be the event of getting the numbers whose sum is less than 7.

The outcomes in favour of event A are (1, 1), (1,2), (1,3), (1,4), (1,5), (2,1), (2,2), (2,3), (2,4), (3,1), (3,2), (3,3), (4,1), (4,2) and (5,1).

Number of favourable outcomes = 15

`:.P(A) = "Number of favourable outcomes"/"Total number of outcomes" = 15/36 = 5/12`