Question

A rectangle is 3 times as long as it is wide. The perimeter is 60cm. Find the dimensions of the rectangle.

Answer 1

width = x 
length = 3x

2(x + 3x) = 60
4x = 60/2
4x = 30
x = 30/4
x = 7.5 cm   ← width 

length = 3x = 3 * 7.5 = 22.5 cm

Answer 2

7.5cm x 22.5cm is the answer.