Final answer:
The cost of one apple is calculated by dividing the total cost, $21.60, by the number of apples, 24, resulting in $0.90 per apple. Hence, option 2 is correct.
Step-by-step explanation:
To find the cost of one apple, you would divide the total cost by the number of apples. In this case, the total cost is $21.60 and the number of apples is 24.
Using the formula:
Cost per item = Total cost / Number of items
We get:
Cost per apple = $21.60 / 24
Cost per apple = $0.90
Therefore, the cost of one apple is $0.90, so option 2 is the correct answer.