Question

An 8-by-15-ft wall has three windows. Each window measures 3 ft by 4ft. The area of three windows is what percent of the area of the entire wall (including the windows)?

Answer 1

Wall 8 ft by 15 ft.

Area of wall:

A = 8 ∙ 15 = 120 ft²


Window 3 ft by 4 ft.

Area of window:

Aw = 3 ∙ 4 = 12 ft²


Area of three windows / Area of wall:

3 Aw / A = 3 ∙ 12 / 120 = 3 ∙ 12 / 10 ∙ 12 = 3 / 10 = 0.3

0.3 ∙ 100 % = 30 %