Question

An ordinary fair die is a cube with the numbers 1 through 6 on the sides. Imagine that such a die is rolled twice in succession and that the faces of the 2 rolls are added together. This sum is recorded of single trial of a random experiment. Event A: The sum is greater than 6 Event B the sum is divisible by 6

Answer 1

A. 5/9 B. 1/6.

Explanation:

Total possible events = 6*6 = 36.

A. The possible combinations for the sum being <= 6 are:

1 ,1 2,2 3,3 1,2 1,3 1,4 1,5 2,1 2,3 2,4 3,1 3,2 3,3 4,1 4,2 5,1

= 16

So Probability of Sum > 6 = (36-16) / 36

= 20/36

= 5/9.

B. Possible combinations where the sum is divisible by 6 are

3,3 2,4 4,2 1,5 5,1. 6,6 = 6.

So the required probability = 6/36

= 1/6.