Question

tow electric bulbs of 100 W each are used for 8 hours daily find the cost of using using them for 1 day if the rate is 75 paise per unit​

Answer 1

Energy of 1 bulb=100/1000 *8=0.8kw/h.

Therefore energy of 2 bulbs=2×0.8=1.6kw/h=1.6"units"

Therefore,cost=75×24=rupees 1800.

And your question is wrong because at last it should be given 75 paise per hour.

Hope this helps.

Answer 2

Answer:

There are two bulbs so the power will be 2×100=200W

Power = Energy/Time

Power = Energy/8

200/1000 =Energy/8

0.2 =Energy/8

0.2×8=Energy

1.6kwh=Energy

1.6×75=120 paise

120/100=1.20 rupees