Question 1142147
2 walls: 17 x 9 = 153 x 2 = 306 square feet
2 walls: 18 x 9 = 162 x 2 = 324 square feet
ceiling: 17 x 18 = 306
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so we have a total area of 306 + 324 + 306 = 936 square feet
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Now deduct the area of the window:
3 feet, 9 inches by 4 feet (convert to inches and calculate):
(36 + 9) x 48 = 2160 square inches. And convert to square feet:
2160/144 = 15 square feet
936 - 15 = 921 square feet is the area to be painted. 
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But you'll be painting it twice (2 coats) so 921 x 2 = 1842 square feet