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