Question

Which number is a common factor of 36, 48 and 66? A. 6 B. 10 C. 8 D. 12

Answer 1

the only number that goes in to all of those is A. 6

Answer 2

Common factors are the product of common prime factors shared by all of the numbers...

36=2*2*3*3, 48=2*2*2*2*3, 66=2*3*11

So the only shared primes are 2*3=6

Thus the only common factor to all of them is 6.