Which pair of numbers is relatively prime?

A.

18 and 45

B.

26 and 91

C.

10 and 33

D.

14 and 63

The answer is C)

The numbers are relatively prime if there is no common factor that divides both of them apart from 1. A) isn't answer because 3 is one of common factors. B isn't answer because 13 is common factor. and D isn't answer because 7 is common factor.

Therefore only 10 and 31 have no common factors other than 1