Question

Donnie practiced for cross country every day last week. The number of miles he ran is equal to a prime number between 15 and 25. Which of the following could be the number of miles Donnie ran ?

Answer 1

Answer: 17, 19, or 23

Those are the prime numbers between 15 and 25

A prime number has factors of 1 and itself only. Something like 22 isn't prime because 2 is a factor. But 17 is prime since the only factors are 1 and 17.