Final answer:
The highest common factor (HCF) of 24 and 60 is 12.
Step-by-step explanation:
The highest common factor (HCF) of 24 and 60 can be found by identifying the common factors of both numbers and choosing the largest one. To do this, we can list the factors of 24: 1, 2, 3, 4, 6, 8, 12, and 24; and the factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60. The largest number that appears in both lists is 12, so the HCF of 24 and 60 is 12.