Question 97669
 
   the perimeter of the rectangle = 60

     let :

      the length of the rectangle = l

      the width of the rectangle = w

   the length is 3 times the width 

     so,  l = 3w

    perimeter of the rectangle = 2 * (l + W )

       so, 60 = 2 * ( w + 3w)

        this formula can be used to find the width.

        once we know the width, we can substitute it in the equation 60 = 2*(l + W )
   to get the length