00:01
An incandescent light bulb uses 40 watts of power, a fluorescent light bulb uses 11 watts of power, and the electrical company charges 11 cents per kilowatt hour.
00:17
How much money can you save over 100 hours if you use the fluorescent light bulb rather than the incandescent.
00:27
To answer this question, note that all we have to do is find the money we can spend, or the money we will spend using a fluorescent light bulb for 100 hours, and the money that it costs to use an incandescent light bulb for 100 hours.
00:45
And then we can find the difference or the amount we can save by subtracting the amount for the incandescent minus the amount for the fluorescent.
00:58
For the first step in our solution, note that we can right away calculate, the rate of money per kilowatt for each of the light bulbs since we know that the overall rate is 11 cents per kilowatt per hour and we know where you're going to use these light bulbs for 100 hours.
01:22
Doing the calculation, we see that 11 cents per kilowatt per hour times 100 hours gives us $11 per kilowatt.
01:37
Now we'll use this to find the cost the cost of using an incandescent light bulb for 100 hours, and the cost of using a fluorescent light bulb for the same amount of time...