D1: lampu= 4x25= 100 watt kipas = 50 watt
TV = 100 watt
D2 : biaya yg dibayar setiap bulan
D3 : lampu+TV+kipas= 100+100+50= 250 watt
penggunaan listrik 1 hari = 10x250= 2500 wh=2,5 Kwh
harga 1 hari = 250,00x2,5= 625,00
harga 1 bulan = 6250,00x30= 18.750,00