The task is to generate the correct answer for a given math problem.

Problem: how many multiples of 7 are there between 10 and 100 ( both are inclusive ) ?
13

Problem: what is the prime factors ’ number of 18 ?
3

Problem: the price of lunch for 13 people was $ 207 including a 15 % gratuity for service . what was the average price per person , excluding the gratuity ?

13.85