2007 AMC 12B Problems/Problem 1

Problem

Isabella's house has 3 bedrooms. Each bedroom is 12 feet long, 10 feet wide, and 8 feet high. Isabella must paint the walls of all the bedrooms. Doorways and wondows, which will not be painted, occupy 60 square feet in each bedroom. How many square feet of walls must be painted?

Solution

There are four walls in each bedroom, since she can't paint floors or ceilings. So we calculate the number of square feet of wall there is in one bedroom:

We have three bedrooms, so she must paint square feet of wall.