A house has three tube lights, two fans and a Television. Each tube light draws 40W. The fan draws 80W and the Television draws 60W. On the average all the tube lights are kept on for five hours, two fans for 12 hours and the television for five hours every day. Find the cost of electric energy used in 30 days at the of Rs. 3.00 per KWH.

Explanation

Power consumption by tube lights in a day `= 40Wxx3xx5H=600WH`
power consumtion by fans in a day `=80Wxx2xx12H=19WH`
Power consumption by television in day `=60Wxx1xx5H=300WH.`
Total power consumption in a day `600+1920+300=2820WH.`
Power consumption for 30 days `=2820xx30=(84cancel(600))/(10cancel(00))=84.6" KWH "`
`"Rate of 1 KWH"="Rs"3//-`
`therefore"Cost of electrical energy used"=84.6xx3="Rs."253.8.`