The task is to generate the correct answer for a given math problem.
--------
Question: Problem: how many multiples of 7 are there between 10 and 100 ( both are inclusive ) ?

Answer: 13

Question: Problem: the average of first 22 natural numbers is ?

Answer: 11.5

Question: Problem: how many positive even integers less than 100 contain digits 5 or 9 ?

Answer:
10