Question

A game of chance consists of spinning an arrow which is equally likely to come to rest pointing to one of the numbers 1, 2, 3,..., 12 as shown in the figure. What is the probability that it will point to a prime number ?

Answer 1

The possible outcomes are 1,2, 3,4, 5................12.

Number of all possible outcomes = 12

Out of the given numbers, the prime numbers are 2, 3, 5, 7 and 11.

Let E₃ be the event of the arrow pointing at a prime number.

Then, number of favourable outcomes =​ 5

∴ P (arrow pointing at a prime number) =  P( E₃)   =`5/12`