Question

In a household an electric bulb of hundred w is used for 10 house and an electric heater of thousand w for 2 hours daily calculate the cost of using the bulb and the heater for 30 days if the cost of 1 unit of electricity energy is 2 rupees

Answer 1

electrical energy consumed by bulb = 100 *10 = 1000wh= 1kwh
electrical energy consumed by heater = 1000*2=2000wh =2kwh
for 30 days = 30 * (1+2)
=30*3
=90kwh
cost = 90*2= rs. 180.

Answer 2

Energy used by heater =100wx(10hx30days) =30000wh =30unit

Energy used by bulbs =1000w(2h ×30days) =60kwh =60units

Total Energy = 60+30 =90Units

Cost =90×2 =180 rupees