So find the area of the rectangle so not the roof. 20 times 32 is 640 ft2. 10 times 32 is 320 but it's a triangle so you divide by 2 to get 160. That makes 800 ft2. Then you subtract all the windows. Each window is 12 ft2 so you subtract 48. Then you have 752. Then you subtract the window on top to get 9. Then you get 743. Then you divide that by 350. Then you get 2.1 gallons which is the answer.
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