A house is fitted with seven tubelights of rating `220 V, 40 W` each , two bulbs of rating `220 V, 60 W`each, five fans each drawing a current of `0.4 at 220 V`, and a heater of resistance `48.4 Omega`. The main line power supplied to the house is at `220 V`. Calculate the bill for the month of january if tubelights and bulbs are used for `6 h` daily, fans for `1 h` daily , and heater for `10 h` daily. The electricity is to cost `Rs. 2 per` unit.

Explanation

Total wattage consumed ( units) is
`( 7 xx 40 xx 6 )/( 1000) + ( 2 xx 60 xx 6)/( 1000) + ( 5 xx ( 220 xx 0.4) xx 1 )/(1000) + ((220)^(2)/( 48.4) xx ( 10)/( 1000))`
`= 12.84` per day
Number of units consumed in one month (jan) is `12.84 xx 31 = 398.04`. Total bill is `2 xx 398.04` = Rs. 796.08`.