Question 415260
Since the perimeter is the sum of all the sides, 2l + w = 158 (1)
Also l - w = 15 (2)
Solving for l in (2) and substituting in (1) we have 2*(w+15) + w = 158
This reduces to 3w + 30 = 158, or w = 128/3 = 42 2/3
Putting this into (2) we have l - 42 2/3 = 15 or l = 57 2/3.