Question

The number of common factors of $20,36$ and $48$ is

Answer 1

Factors of $20=1,2,4,5,10,$ and $20$
Factors of $36=1,2,3,4,6,9,12,18$ and $36$
Factors of $48=1,2,3,4,6,8,12,16,24$ and $48$
Hence, common factors of $20,36,48$ are $1,2,4.$ So, total numbers of common factors is equal to $3.$