To determine which factors of 20 are also factors of 30, we first need to list the factors of each number.
The factors of 20 are: 1, 2, 4, 5, 10, and 20.
The factors of 30 are: 1, 2, 3, 5, 6, 10, 15, and 30.
Now, we can identify the common factors by looking for numbers that appear in both lists. The common factors of 20 and 30 are: 1, 2, 5, and 10.
In conclusion, the factors of 20 that are also factors of 30 are: 1, 2, 5, and 10.