Question

Which pair of numbers is relatively prime?

A.
12 and 25

B.
18 and 39

C.
9 and 24

D.
24 and 45

Answer 1

Relatively prime means that the only factor the numbers have in common is the number 1. The answer is A. 12 and 25 have no other factors in common other than 1.

Answer 2

A.12=3*4, 25=5*5
Each member of the other three pairs has a factor of three.