Question

Question 20(ii)
Two dice are thrown simultaneously. What is the probability that the sum of the numbers appearing on the dice is a prime number?

Answer 1

Two dice are thrown simultaneously.
So, the total number of possible outcomes = 36
Sum of the numbers appearing on the dice is a prime number i.e. 2, 3, 5, 7 and 11.
So, the possible ways are (1,1), (1,2), (2,1), (1,4), (2,3), (3,2), (4,1), (1,6), (2,5), (3,4) (4,3), (5,2), (6,1), (5,6) and (6,5).
Number of possible ways = 15
$\therefore$ Required probability $=\frac{15}{36}=\frac{5}{12}$