Hello.
First, let's clarify what the G.C.F. means.
It means "Greatest Common Factor"
So, let's find the Greatest Common Factor of 15 and 48.
First, let's list all the factors of 15:
1, 3, 5, 15
Here are the factors of 48:
1, 2, 3, 4, 6, 8, 12, 16, 24, 48
Therefore, the GCF of 15 and 48 is 3.
I hope it helps.
Have a nice day.