Question 260084
The width of a rectangle is 4 cm less then the length. The perimeter is 72 cm. What is the width of the rectangle? 

Let l be the length and w the width of the rectangle. Then the perimeter = 2*l + 2*w

We also know that w = l - 4 or equivalently l = w + 4:

Perimeter = 72 = 2*l + 2*w.

Substituting w + 4 for l in the equation above we have:

72 = 2*(w+4) + 2*w

Solve the above for w.