Question

9 and ___ are a co-prime pair.

• A. 3
• B. 18
• C. 24
• D. 35

Answer 1

The correct option is D 35

Two numbers are co-prime if their HCF = 1
Consider option (a),
HCF of 9 and 3 = 3
Consider option (b),
HCF of 9 and 18 = 9
Consider option (c),
HCF of 9 and 24 = 3
Consider option (d),
HCFof 9 and 35 = 1
Hence, 9 and 35 are a co-prime pair.