Question

Which of the following is a composite number 63 ,31, 13 ,61

Answer 1

A composite number is a number that is not prime, that is, it has factors.

Here, it's 63: it's divisible by 3:

63/3=21

and then by 3 again:

21/3=7

and only 7 is a prime.

so 63 is the answer