Question

Which numbers are composite numbers 3 10 17 24 31 38

Answer 1

10, 24, and 38.

A composite number is the opposite of a prime number: it can be dived by numbers other than 1 and itself.

Answer 2

A composite number is a number that isn't prime. That means it has more than the factors of 1 and itself. 
3 is prime because its only factors are 3 and 1. 
10 is composite b/c its factors are 10 and 1, and also 5 and 2.
17 is prime.
24 is composite (8 and 3, 12 and 2)
31 is prime.
38 is composite (19 and 2).