Calculate the electricity bill amount for a month of April, if 4 bulbs of 40 W for 5 h, 4 tubelights of 60 W for 5 h, a TV of 100 W for 6 h, a washing machine of 400 W for 3 h are used per day. The cost per unit is Rs 1.80.

Electric energy consumed per day by 4 bulbs = 4x40 x5 = 800Wh

Electric energy consumed per day by 4 lights = 4x60x5 =1200 Wh

Electric energy consumed per day by TV = 100x6 = 600 Wh

Electric energy consumed per day by washing machine = 400x3 =1200 Wh

.’. Total electric energy consumed by all electric appliances = (800+ 1200 + 600+ 1200)Wh = 3800 Wh = 3.8 kWh =3.8 units

Total electric energy consumed in the month of April (30 days) = 3.8 x 30 = 114units

Cost of one unit = Rs. 1.80

Cost of 114 units = 114 x 1.80 = X 205.20 .:. Electricity bill amount = Rs 205.20