P = Perimeter = 2(length) + 2(width). Let the width be x; then if the length is 5 times longer than the width, the length is 5x.
Plug these values into the Perimeter equation P = 2(length) + 2(width):
P = 2(5x) + 2(x), or P = 12x, and this is known to have the value 192 units. Solve for the width, x:
(192 units) = 12x gives us x = 16 units. Then the length is 5(16 units) = 80 units.
Check: Does 2(80 units) + 2(16 units) = 192 units? If so, then our width (16) and length (80) are correct.
