SOLUTION: Sergio plans to paint the 4 walls of his room with 1 coat of paint. The walls are rectangular, and, according to his measurements, each wall is 10 feet by 15 feet. He will not need

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Question 256018: Sergio plans to paint the 4 walls of his room with 1 coat of paint. The walls are rectangular, and, according to his measurements, each wall is 10 feet by 15 feet. He will not need to paint the single 3-foot-by-5-foot rectangular window in his room and the 3 -foot-by- 7-foot rectangular door. Sergio knows that each gallon of paint covers between 300 and 350 square feet. If only 1-gallon cans of paint are available, which of the following is the minimum number of cans of paint Sergio needs to buy to paint his walls?
a) 1 b) 2 c) 3 d) 4 e) 5


Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
he has to paint 4 walls.

each wall is 10 feet by 15 feet.

the area of each wall is therefore 10 * 15 = 150 square feet.

4 * 150 = 600 square feet.

the window is 3 feet by 5 feet = 15 square feet.

the door is 3 feet by 7 feet = 21 square feet.

since these do not need to be painted, he subtracts them from the total square feet that have to be painted to get:

600 - 15 - 21 = 600 - 36 = 564 square feet.

the maximum coverage for each can is 350 square feet.

564 / 350 = 1.62.... which means he will need at least 2 cans.

the minimum coverage for each can is 300 square feet.

564 / 300 = 1.88 which means he will still need at least 2 cans.

he has to get 2 cans of paint either way.

answer is selection b.