TOLONG dijawab.......please.....pakai CARA

40% + 15% + 25% = 80%
Pensil = 20%
25/100% = 20 Lusin

20 Lusin itu 1/4, dikali 4 = 80 Lusin Totalnya 
20/100 x 80 = 1600/100 = 16 Lusin (C)