College

Which pairs of numbers have a greatest common factor of 6? Select all that apply.

A. 18 and 24
B. 21 and 36
C. 30 and 48
D. 36 and 60
E. 48 and 72
F. 54 and 84

Answer :

To determine which pairs of numbers have a greatest common factor (GCF) of 6, follow these steps:

1. Understand the Greatest Common Factor (GCF): The GCF of two numbers is the largest number that divides both of them without any remainder.

2. Check Each Pair:
- A. 18 and 24:
- Factors of 18: 1, 2, 3, 6, 9, 18
- Factors of 24: 1, 2, 3, 4, 6, 8, 12, 24
- Common factors: 1, 2, 3, 6
- The greatest of these is 6.

- B. 21 and 36:
- Factors of 21: 1, 3, 7, 21
- Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36
- Common factors: 1, 3
- The greatest of these is 3.

- C. 30 and 48:
- Factors of 30: 1, 2, 3, 5, 6, 10, 15, 30
- Factors of 48: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
- Common factors: 1, 2, 3, 6
- The greatest of these is 6.

- D. 36 and 60:
- Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36
- Factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
- Common factors: 1, 2, 3, 4, 6, 12
- The greatest of these is 12.

- E. 48 and 72:
- Factors of 48: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
- Factors of 72: 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72
- Common factors: 1, 2, 3, 4, 6, 8, 12, 24
- The greatest of these is 24.

- F. 54 and 84:
- Factors of 54: 1, 2, 3, 6, 9, 18, 27, 54
- Factors of 84: 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84
- Common factors: 1, 2, 3, 6
- The greatest of these is 6.

3. Conclusion:
Based on the above evaluation, the pairs that have a greatest common factor of 6 are:
- A: 18 and 24
- C: 30 and 48
- F: 54 and 84

Therefore, the correct answers are A, C, and F.