Greeting to everyone, this is my first post.

I'm studying for my California C-10 exam this month.

I'm stumped, and now I'm downright curious about an exam question. I'm using some sample practice exams that I bought from a business called Contractors State License Schools, which is a contractors exam prep school here in California. (I'm presuming they've used spies to find out what the questions are over a long period of time, or something like that.)

I've use one of these schools before, and I've learned that sometimes, when I think the school is giving me a really wacky question, it turns out that the doggone Contractors State License Board really does ask that question. Here's the one I'm scratching my head about

:

"In a school, twenty 75-watt incandescent lights were replaced with twenty 20-watt fluorescent bulbs. If they pay $0.10/KWH, how much will they save in a year?"

At 55 W savings and 20 bulbs, which is 1.1 kW, there is a savings of $.11 an hour. Great! No problem!

But how many hours does the school run their lights? Since the answer is $275, it calculates out to 2500 hours. Does anybody know how many hours a school has their lights on? There's security lights and gym lights and hallway lights and office lights, and then there's special events, etc. Why do they ask this question without more information? Math I can do. But I need more data. Grr.

Any advice?

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