In a residence 4 tubelights each of 40W are operated daily for 5 hour and 3 fans each of 120 W are operated daily for 4 hour. What would be the amount of electricity bill at ₹ 5 per unit for the month of September?

Answer

₹ 336

Explanation

Total electrical energy consumed through four tubelights in a day
`=4xx40Wxx5h=800Wh`
Total electrical energy consumed through three fans in a day `=3xx120Wxx4h`
`=1440Wh`
`therefore` Total electrical energy consumed in a day = `800Wh+1440Wh`
`=2240Wh`
`=2.240xx10^(3)Wh`
`=2.24kWh`
= 2.24 unit (`because` 1 kWh = 1 unit)
Total units consumed in the month of September = `30xx2.24`
= 67.2 units
Now, as consumption expense is ₹ 5 per unit, electricity bill for the month of September = `5xx67.2=₹336`.
Eletricity bill : ₹ 336