John uses a 75-watt electric fan for 8 hours a day. How much kWh of electric energy does he consume per month (30 days) for using the electric fan?
Let's be accurate as possible and think first.
18
In a day, John uses 75x 8 = 600 watts.

So in a month, he uses 600 x 30 = 18 000 watts.

Since there are 1000 watts in 1 kilowatt, then John uses 18000 / 1000 = 18.

.

The answer is 18