Question

Student in a hostel room use 100w electric lamp for 5 hours a day and a radiator of 500w for one hour a day .calculate the cost of running of these appliances for 30 days at rate of 30 paise per unit

Answer 1

Answer:

Rs. 90

Explanation:

Electric Lamp,

Power = 100W

Time = 5 hours

Units per day = (Watt*Hours)/100

= [ (100*5)/100 ] kWh

= [ 500/100 ] kWh

= 5 kWh

= Units in a month = (5*30) kWh

= 150 kWh

Radiator,

Power = 500W

Time = 1 hour

Units per day = (Watt*Hours)/100

= [ (500*1)/100 ] kWh

= [ 500/100 ] kWh

= 5 kWh

= Units in a month = (5*30) kWh

= 150 kWh

= Total Units = (150+150) kWh

= 300 kWh

= Cost of 1 kWh = 30p

= Cost of 300 kWh = (300*30) paise

= 9000 paise

= Paise to Rupees = Rs. 1 = 100p

= 9000 paise = Rs. (9000/100)

= Rs. 90

Hope this helps.