Amanda wants to paint the walls of a room. She knows that each can of paint contains one gallon. A half gallon will cover 55 square feet of wall. Each of the four walls is 10 feet high. Two of the walls are 10 feet wide and two of the walls are 15 feet wide. How many 1-gallon buckets of paint does Amanda need to buy in order to fully paint the room?

First, we must calculate the area of the walls Amanda wants to paint. Two of the walls are \(10 \times 10\) and two of the walls are \(10 \times 15\) :
\(2 \times (10 \times 10) = 200\)
\(2 \times (10 \times 15) = 300\)
So the total square footage of the walls is 500.
If a half gallon of paint will cover 55 square feet, then each gallon will cover 110 square feet. Four gallons would only cover 440 square feet. Five gallons will cover 550 square feet, which will be enough for all 500 square feet of walls.