Question

Two dice, one blue and one grey, are thrown at the same time. Write down all the possible outcomes. What is the probability that sum of the two numbers appearing on the top of the dice is 

(i) 8 (ii) 13 (iii) less than or equal to 12?

Answer 1

Outcomes= (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)

(i) Sum is 8

Favourable outcomes = (2, 6), (3, 5), (4, 4), (5, 3), (6, 2) = 5

P(sum is 8) = 5/36

(ii) Sum is 13

Favourable Outcomes = 0

P(sum is 13) = 0

Since the maximum sum that can be obtained is 12.

(iii) Less than or equal to 12

Possible outcomes = All outcomes have sum less than or equal to 7.

P(less than or equal to 12) = 1