Relatively prime means there are no number greater than 1 that divides them both.
Find the GCF for each set:
A. 68 and 119
68: 1 , 2, 4, 17, 34,68
119: 1, 7, 17
Both numbers can be divided by 1 or 17 so are not relative.
B.
40 and 395
are both divisible by 1 and 5 so are not relative.
C. 119 and 715
Are both only divisible by 1, so are relative.
D. 63 and 56
Are divisible by both 1 and 7 so are not relative.
The answer is C. 119 and 715