Vishva noticed in a dhaba around 50 bulbs, each of 100 W all were glowing. She calculated the cost of electricity consumed in one hour and told the dhaba owner to reduce the expenses and at the same time save electricity by using CFL bulbs instead of ordinary filament-type bulbs.
What would be the cost of electric energy if 50 bulbs, each of 100 W. are used for one hour? 1 unit costs Rs 5.

Explanation

The cost of electricity consumed when 50 bulbs are used for 1 hour
=(number of units consumed) `xx` Rs 5 per unit
`= (50 xx 100/1000 kW xx1 h) xx (Rs 5)/(1 "unit")`
`= (5kWh) xx(Rs 5)/(1 "unit")`
`= Rs 25`