efficiency: 75 kW-hr/day, 500 W/m^2 for 10 hrs; if 12.5% eff

[huntinghawk]

You need 75 kWh per day for your house, and you can collect 500 W/m2 from the Sun 10 hours a day on your plot of land. If the efficiency of the solar panels you are intending to put on your roof is 12.5%, how large must your roof be?

I am not sure where to begin. Any help in getting me started and explaining what to do and how to do it would be most appreciated. Thank you.

 

[stapel]

How is "efficiency" defined? Are you supposed to assume that you can convert only 12.5% of the five hundred watts that are collected by each square meter of solar panel?

Thank you!

Eliz.

 

[huntinghawk]

according to our readings "efficiency" is defined as Efficiency = work done/energy used.

as far as your second question, it is unclear to me as to what is assumed and what is not. What I posted was the exact question.
The reading that I had done that goes with this question was on chapter 5 of "Touch This! Conceptual Physic for Everyone" by Paul G. Hewitt.
The question was one from my teacher though.