You want to paint a wall that is 71/2 feet tall and 93⁄4 feet wide with two coats of paint. How many cans of paint would you need to buy if one can covers 20 square feet?

8 cans

Step-by-step explanation:

The area of the wall is the product of its dimensions:

(7.5 ft) · (9.75 ft) = 73.125 ft^2

Twice that area is ...

2 · (73.125 ft^2) = 146.25 ft^2

At 20 ft^2 per can, the number of cans required is ...

(146.25 ft^2) / (20 ft^2/can) = 7.3125 cans

We assume you cannot buy a partial can, so ...

you would need to buy 8 cans of paint for the wall.