The length of a rectangle is 6cm longer than its width. If the perimeter of the rectangle is 60cm, find its length and width.

The perimeter can be calculated with 2 (length+width).

If we let the width be x then the length will be x+6.

If we put this in the equation you get

60=2 (x+x+6)

60=2 (2x+6)

60=4x+12

48=4x

12=x

So the width is 12cm.

We substitute this into x+6.

12+6=18

The length is 18cm.