An electric refrigerator rated 300 W is used for 8 hours a day. An electric iron box rated 750 W is used for 2 hours a day. Calculate the cost of using these appliances for 30 days, if the cost of 1 kWh is Rs. 3/-
The total energy consumed by the refrigerator in 30 days = 400 × 8 × 30 = 96000 Wh = 96 kWh The total energy consumed by the iron box in 30 days =750 × 2 × 30 = 45000 Wh = 45 kWh The total energy consumed by the refrigerator and iron box is = 96 kWh + 45 kWh = 141 kWh The sum of bill amount for 141 kWh at rate of Rs. 3 per 1 kWh is =141 × 3 = Rs. 423
