The perimeter of a picture frame has to be between 36cm and 48cm. If the length is four cm longer than the widyh, find a range for the width
let the width be w
the length is w+4
36 <= 2(w + w+4) <= 48
18 <= 2w+4 <= 24
9 <= w+2 <= 12
7 <= w <= 10