Question

What are co-primes? Give examples of five of co-primes. Are co-primes always prime? If no, illustrate your answer by an examples.

Answer 1

Two numbers are said to be co-primes if they do not have any common factor other than $1$.
For example: $(2,3),(3,4),(4,5),(5,7)$ and $(13,17)$ are co-primes. Because each pair has no common factor other than $1$.

Two co-prime numbers need not be both prime numbers.
In above example let us take an coprime $(4,5)$ but here $4$ is not a prime number though the pair is coprime.
Hence, co-prime numbers need not be prime numbers always.
Examples: $(3,4),(6,7)$ and $(4,13)$