Are 15 and 42 co-prime

Answer 1

If the GCF of two numbers is 1 then the numbers are co-prime or a pair of numbers which have only 1 as their common factoris called co-prime.

Let us check if 15 and 42 share any common factors other than 1.

Factors of 15: 1, 3, 5 and 15.

Factors of 42: 1, 2, 3, 6, 7, 21 and 42.

As it can be seen that 3 is a common factor or GCF of 15 and 42.

So, 15 and 42 are not co-prime.