Which type of numbers are NOT co-prime?

Question

Question

This question was previously asked in

SSC GD Constable (2022) Official Paper (Held On : 31 Jan 2023 Shift 3)

Answer 1

Concept:

Numbers that have any common factor other than 1 are not co-prime

Calculation:

Any two prime numbers:

Prime numbers only have two factors, 1 and the number itself.

Therefore, any two prime numbers are always co-prime.

Any two consecutive odd numbers:

Consecutive odd numbers, such as 3 and 5 or 7 and 9, always have a common factor of 1

Hence are co-prime.

Any two consecutive numbers:

Consecutive numbers such as 4 and 5 or 9 and 10 always have a common factor of 1

Hence are co-prime.

Any two consecutive even numbers:

Consecutive even numbers such as 2 and 4 or 8 and 10 always have a common factor of 2.

Therefore, they are NOT co-prime.

Therefore, 'Any two consecutive even numbers' are NOT co-prime numbers.