A rectangular lightswitch plate is made according to the fol

A rectangular light-switch plate is made according to the following dimensions. The length is 8 inches, and the width is 6 inches; a rectangular hole measuring 1 inch by 3 inches is left in the center. (See diagram below) (a) How many square inches in area is the light-switch plate (the shaded region)? (b) If the cost to construct the plate is $3.50 per square inch, what is the construction cost?

Solution

a)
\"area of light-switch plate\" = \"area of plate\" - \"rectangular hole\"
\"area of light-switch plate\" = (8)(6) - (1)(3)
\"area of light-switch plate\" = 48 - 3
\"area of light-switch plate\" = 45 square inches
.
b)
cost = 45*3.50 = $157.50