Answer:
$1095
Explanation:
You first have to find out the area of each rectangle. In order to do that you need to use the formula length times width. In this case, the length is 8 and the width is 10. 8 times 10 is 80.
Since there are three walls of the same area, you multiply 80 by 3. This is 240.
Now you need to find the area of the door, you do this by multiplying 3 times 7, which is 21.
Now you will subtract 21 from 240 which is 219.
Since each square foot is $5, you need to multiply 219 by 5. You end up with 1095!