Question

A rectangular wall has a length of 12 ft and a width of 8 ft. The wall has two rectangular windows. Each window has a width of 3 ft and a height of 5 ft. Andrea chooses a point on the wall at random to test a new paint color. What is the probability she could choose a point on a window? Enter your answer, as a decimal rounded to the nearest hundredth, in the box. P(choosing a point on a window) = The figure shows two rectangles inside a larger rectangle. The two smaller rectangles each have a length of 3 feet and a width of 5 feet. The larger rectangle has a length of 12 feet and a height of 8 feet.

Answer 1

The wall area (including windows) is 
  A = (12 ft)×(8 ft) = 96 ft²

The area of one window is
  A = (3 ft)×(5 ft) = 15 ft²a

The total window area as a fraction of the total wall area is
  P(window) = (2×15 ft²)/(96 ft²) = 5/16 = 0.3125


The probability that Andrea will randomly choose a spot on a window is
  P(choosing a point on a window) ≈  0.31.