Jawabanmu

2014-03-25T00:14:09+07:00
Biaya total = (4x-1200+1200/x).x = 4x^2 -1200x+1200.. agar minimum mka turunan = 0 shg 8x -1200 = 0 -> 8x = 1200 -> x = 150 jam
2014-03-25T00:18:08+07:00

0.25 ................................