GMAT Problem Solving (PS) | Re: The ratio by weight, measured in pounds, of books to clothes

Ratio
B:C:E = 8:5:3

Total weight of items = x

Weight of books = 8x/16
Weight of clothes = 5x/16
Wegith of electronics = 3x/16

New total weight of items = (x-4)
Weight of clothes = 5x/16 - 4 = (5x-64)/16

New Ratio B:C:E =
8x/16(x-4) : (5x-64)/16(x-4) : 3x/16(x-4)
8x : 5x-64 : 3x

We're told B:C = 16:5
So B/C = 16/5 = 8x/5x-64
80x - 1024 = 40x
40x = 1025
x = 25.6

Electronics = 3x/16 = 4.8 pounds ~ 5 pounds