Question 1010900
Perimeter P = 2L + 2W = 42.
We also have L = 3 + 2W.
Now substitute that into the first equation and get
2(3 + 2W) + 2W = 42
6 + 4W + 2W = 42
6W + 6 = 42
6W = 36
W = 6 inches
L = 3 + 2(6) = 15 inches