Question

Bens date of birth is a prime number between 15 and 25. This number has 57 as a multiple.

Answer 1

this number would be 19 because 19 is a prime number and 19*3 is 57, making 57 a multiple of 57

Answer 2

The prime factorization of 57 is 3 x 19. Since 19 is the only prime factor of 57 between 15 and 25, it must be 19.