Question

Which of the following pair of numbers have 1as their only common factor?

• A. 75, 36
• B. 15, 17
• C. 18, 6
• D. 10, 45

Answer 1

The correct option is B 15, 17

Pair 1:
75: 1, 3, 5, 15, 25, and 75
36: 1, 2, 3, 4, 6, 9, 12, 18, and 36
Common factors: 1, and 3

Pair 2:
15: 1, 3, 5, and 15
17: 1, and 17
Common factor: 1

Pair 3:
18: 1, 2, 3, 6, 9, and 18
6: 1, 2, 3, and 6
Common factors: 1, 2, 3, and 6

Pair 4:
10: 1, 2, 5, and 10
45: 1, 3, 5, 9, 15, and 45
Common factors: 1, and 5