Mr. magoo needs to paint on of his bedrooms that is 15ft by 20ft. if he paints only the walls, and each gallon of paint covers 100ft2, how many gallons of paint will he need?

To solve this problem you must apply the proccedure shown below:

1. You have that the total area is obtained by applying the formula for calculate the area of a rectangle and multiply it by the four walls:

2. You know that each gallon of paint covers 100 ft², therefore, you can calculate the amount of gallons needed (which you can call ), if you divide the total area of the walls by the area covered by each gallon:

The answer is: 12 gallons.