Question

There are 25 prime numbers less than 100.

Some of these are two-digit prime numbers.
What fraction of two-digit prime numbers contain the digit 9?
Express this fraction in lowest terms.

Answer 1

6/25.

Explanation:

They are 19, 29, 59, 79, 89 and 97.

A total of 6.

So the required fraction is 6/25.