Perimeter of 60, length is 3 times the width, what are the dimensions

Length - l

Width - w

Given,

Perimeter = 60

2 (l + w) = 60

l + w = 30

l = 30 - w

Given,

l = 3w

30 - w = 3w

4w = 30

- - - w = 7.5

- - - l = 3w = 3 * 7.5 = 29.5

Hence, the length of the rectangle is 29.5 and the width is 7.5