10.A room has two tube lights, a fan, and a TV.Each tube light draws 40W, the fan draws 80 W and TV draws 60W.On an average, the tube lights are kept on for 5 hours, the fan for 12 hours and the TV for 8 hours every day.The rate of the electrical energy is Rs.3.10 per kWh.Calculate the cost of electricity used in that room in a 30 day month.

We have,

2 tube lights each of 40 W kept ON for 5 h a day for 30 days,

Energy consumed is = (2 × 40 × 5 × 30) Wh = 12000 Wh = 12 kWh

1 fan of 80 W kept ON for 12 h a day for 30 days.

Energy consumed is = (1 × 80 × 12 × 30) Wh = 28800 Wh = 28.8 kWh

1 TV of 60 W kept ON for 8 h a day for 30 days.

Energy consumed is = (1 × 60 × 8× 30) Wh = 14400 Wh = 14.4 kWh

So, total energy consumed is = 12 + 28.8 + 14.4 = 55.2 kWh

The cost of electricity for the month is = Rs 55.2 x 3.10 = 171.12 rupees