# How do I estimate hours of use and find power for appliances?

1. The problem statement, all variables and given/known data

Please look at the attachment, I’m not sure how to go about figuring out the estimated hours of use per week for the appliances, and the Power(wattage) as well. I figured to find out one you would need the other, they are given in the answers section but I need to know how to find out for myself. It should be really obvious but for some reason I’m just stumped on this.

2. Relevant equations

1kWh=1000J/s * 3600
P=W/Δt

3. The attempt at a solution

So the energy consumed per week for each appliance was easy to find out, by dividing the energy consumed per year with the number of weeks in a year.

This gave, 5.08kWh/week for the TV, and 17.5kWh/week for the dryer
Using these to multiply the given cost of electricity gave the Running cost per week, which was \$0.30/week for the TV, and \$1.05/week for the dryer.

Now comes the part which asks for the estimated hours of use per week and Power, which I just couldn’t seem to figure out where to start. Any guidance to redirect my train of thought could even be greatly helpful, or just straight up lay the math out for me would be even better.

In the answers section, The "Estimate hours of use per week" was 45h/week for TV, and 5h/week for the Clothes dryer.
The power for tv is 0.11kW or 111W , and for dryer is 3.5kW or 3500W
I know the total energy spent per week divided by either gives the other, but how do i find out one without the other?

Thanks.

http://ift.tt/1iT32Qh