Answer: 24 cups
Explanation:
Given : A recipe for 1 apple pie calls for 6 cups of sliced apples.
Then, By applying the famous UNITARY METHOD, we have
1 apple pic= 6 cups
Then, 4 apple pies =

i.e. 4 apple pies = 24 cups
Therefore, the number of cups of sliced apples are needed to make 4 apple pies = 24