Question

Which of the following is a pair of co-primes?

• A. (16, 62)
• B. (23, 92)
• C. (18, 25)
• D. (21, 35)

Hint:

To determine if two numbers are co-prime, find their HCF. If the HCF is 1, the numbers are co-prime.

Answer 1

The Correct Option is C

Two numbers are co-prime if their H.C.F is 1.
Let's check the H.C.F of the pairs:
1. For (16, 62), the H.C.F is 2 (since both are divisible by 2).
2. For (23, 92), the H.C.F is 23 (since 92 is divisible by 23).
3. For (18, 25), the H.C.F is 1 (since they have no common factors other than 1).
4. For (21, 35), the H.C.F is 7 (since both are divisible by 7).
Since the H.C.F of (18, 25) is 1, they are co-primes.