Question

the length of a rectangle is three less than twice its width. If the perimeter is 48, find the length.

Answer 1

length = 15

let the width = w then length = 2w - 3

Perimeter = 2(length + width)

                = 2(2w - 3 + w) = 2( 3w - 3) = 6w - 6 = 48

hence 6w = 48 + 6 = 54 ⇒ w =$\frac{54}{6}$= 9

Thus length = 2w - 3 = (2× 9) - 3 = 18 - 3 = 15