How might I solve this

Question

The width of a rectangle is one
quarter its length. The perimeter of the
rectangle is 30cm. Write and solve an
equation to find the width and length
of the rectangle.

Answer 1

Rectangle with width a and length b: b=4a. Perimeter p=2(a+b)=130 cm

2(a+b)=130

a+b=75

a+4a=75

5a=75

a=15 cm (this is  width)

b=4*a=4*15=60 cm (length)