Write a set of three numbers that have a GCF of 13.

Let a, b and c be 3 numbers whose Greatest Common Factor is 13.

This means that all a, b, and c are multiples of 13, and the three of them have no other common factor (except1)

So we can construct a, b and c as follows:

a=13*2*3, b=13*2*5, c = 13*7

a=78, b=130, c=91

Answer: {78, 130, 91}