Question

A game consists of a spinning arrow that comes to rest pointing at one of the numbers $1,2,3,4,5,6,7,8,9,10,11,12$; as shown below.
If the outcomes are equally likely, find the probability that the pointer will point at a prime number.

Answer 1

We have,

Total number of possible outcomes $=12$

Favorable outcomes for a prime number are $2,3,5,7,11$

So, the number of favorable outcomes $=5$

Hence, P(the pointer will be at a prime number) $=5/12$