Puzzle for March 26, 2010

Tomorrow is the Earth Hour celebration. For the hour on Saturday, you should not use any electricity. Turn off your computers, your lights, your refrigerator :)

* Assuming that the average home normally has 8 electric lights burning at night. (Apartment dwellers and students living in dorms have fewer than 8 lights burning at night. Families living in large houses often have more than 8 lights burning.)
* Let’s say that of those 8 lights, 6 are already equipped with compact fluorescent bulbs and 2 are still burning incandescent bulbs.
* Assume the electricity use of the CFLs averages 18 watts per bulb and the incandescent bulbs average 75 watts per bulb. The total electricity need for these 6 bulbs is ___ watts.
* The idea of Earth Hour is to turn off your lights for one hour.
* A kilowatt is equal to 1000 watts. Using 1 kilowatt for 1 hour is what your electric company describes as 1 kilowatt-hour (kWh).
* How many KWh will our lights burn during the hour? * So, how many pounds of CO2 will you save by turning off those 8 light bulbs during your Earth Hour.

See The Solution