Which of the following is a pair of co-prime numbers?

Correct option is B

Solution:

Two numbers are said to be co-prime if their greatest common divisor (GCD) is 1, i.e., they do not have any common factor other than 1.

Let's check the GCD of each pair:

A) 455, 49

- HCF of 455 and 49 is 7, so 455 and 49 are not co-prime.

2. B) 81, 16

- HCF of 81 and 16 is 1, so 81 and 16 are co-prime.

3. C) 363, 77

- HCF of 363 and 77 is 11, so 363 and 77 are not co-prime.

4. D) 52, 24

- HCF of 52 and 24 is 4, so 52 and 24 are not co-prime.

Thus, the pair of co-prime numbers is 81 and 16.