NEED EXPLANATION NOT ANSWER
Bethany is building storage boxes. Each box will have a length of 6 feet, a width of 3 1/2 feet, and a height of 5 1/2 feet. A quart of paint covers 100 square feet.

How many quarts of paint does Bethany need to buy in order to paint 5 boxes?

Responses

4 quarts
4 quarts

6 quarts
6 quarts

7 quarts
7 quarts

8 quarts
The answer is 8 quarts,but I want an explanation