Pleaee solve problem

Dear student,
The basic unit of electricity is kilowatt hour (kWh).
1 one kilowatt hour is the energy used by ten 100 watt bulbs in one hour.
So,
Energy used by bulbs in 5 hours = 5kWh
Therefore, energy used in 30 days = 5 x 30 
                                                             = 150 kWh or 150 units
Cost of electricity = 150 x 2
                                = 300 rupees.

Regards.