What is the highest common factor (HCF) of 12, 15, and 60?

• A. 1
• B. 3
• C. 5
• D. 15

Answer: (B)

To determine the highest common factor (HCF) of the numbers 12, 15, and 60, it's necessary to find the factors for each number first and then identify the largest factor they all share.

Starting with the factors:

• The factors of 12 are: 1, 2, 3, 4, 6, and 12.

• The factors of 15 are: 1, 3, 5, and 15.

• The factors of 60 are: 1, 2, 3, 4, 5, 6, 10, 12, 15, and 60.

Next, we look for common factors among these numbers:

• The common factors of 12, 15, and 60 are: 1 and 3.

The HCF is defined as the largest common factor. In this case, the greatest of the common factors identified is 3.

Thus, the highest common factor of 12, 15, and 60 is 3. This means that 3 is the largest number that can divide each of the three numbers without leaving a remainder, which is why it is the correct choice in this context.