Question 789813
l = 3w

P = 2l + 2w
96 = 2(3w) + 2w
96 = 6w + 2w
96 = 8w
96/8 = 8w/8
12 = w

check:

96 = 2(3(12)) + 2(12)
96 = 2(36) + 24
96 = 72 + 24 
96 = 96