It can be. 50 is a common factor of 100 and 150.
2
The GCF is 50.
5
Since 54 is a factor of 108, all of its factors are common.
7
The GCF is 18.
5 and 50
They are both positive integers under fifty, but the only factor they have in common is 1.
The GCF is 2.
The greatest common factor of sixteen and fifty-two is four.
Everything except 1, 2, 3 and 6.
No.