If one quart of paint is exactly enough for two coats of paint on a 9-foot by 10-foot wall, how many quarts of paint are needed to apply one coat of paint to a 10-foot by 12-foot wall? Express your answer as a common fraction
Two coats of paint will cover 2 * 9 *10 = 180 sq ft
And a 10 * 12 wall = 120sq ft
So
1 qt / 180 sq ft = ? qts / 120 sq ft cross-multiply
1 * 120 = 180 * ? divide both sides by 180
120 / 180 = ?
2 / 3 qts = ? = amt to cover the 10 x 12 wall
