Basic KWH question from exam prep course seems to be broken or I'm a total moron.....

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charlie b said:
The person who wrote the test question failed in his or her responsibility to provide sufficient information to allow the student to obtain an answer. I would not concern myself over finding how they came up with one of the four possible answers. You can't get it right because the question's author got it wrong. You should find another school. Oh wait, you already did that. Good decision.
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:thumbsup:
 
Before discrediting the test authors, I comment on the possibility of exam instructions or directions by the instructor about what the test covers. Such as materials from chapters so and so in the text book. Huge assumptions that can never be made in real life are often made in test questions.

I could select any single answer from those four and write BS to justify the correctness. An account with multiple facilities that size wouldn't be billed on just energy charge. If I so wanted I could place these 20 bulbs in some place used only by drama or theatre department only and schedule the class to meet in coincidence with the school's historical peak usage period so the added demand stands on top of the summit. I'll choose the rate schedule from wherever I want.

The class could only meet for 6 hours a month and i could make it appear on paper as $200 a year difference by the cost of 1.1 x kW demand charge.

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?
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Well the question didn't ask how much they would save on energy charge. Realistically, where are incandescent lamps still used in schools aside from janitorial closets or theater/stage departments?
 
Electric-Light said:
Given the choices, it can not be C or D since thy exceed the theoretical maximum when you're working within the constraints provided.

I would call A or B correct. It doesn't say where the lamps are changed. No schools I am aware of leave the entire premise pitch dark at any given moment of the year. There are lights that remain on 24/7 or at least dusk to dawn.
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No it's not. 20 bulbs x 75W ea = 1.5kw. 20 @ 20W ea = 400W, difference of 1.1kw/hr, or, x $0.10kw=hr, 11 cents an hour difference in run cost. 8760 hours/year x .11 = $963.6/year if the bulbs ran 24/7/365. There is nothing in the wording of the original question to indicate run time/day.

ggunn said:
If that was the mindset of the author of the question, my opinion is that he (or she) should look for another job. The purpose of the prep test is to prepare the student for the real world exam; if what you describe is the "correct" method of determining the answer to the question, the author has missed the point by a light year or two.
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Agree and I mentioned as much in my initial post; w/o multiple choice no one would get $275.
 
The examiner may be pardoned if he had just mentioned ''the number of usage hours is an integer'' in the question. Then the question is in MENSA range and the answer is necessarily 275.
 
: reply and thx to all those who read and replied to this

: reply and thx to all those who read and replied to this

Sahib said:
The examiner may be pardoned if he had just mentioned ''the number of usage hours is an integer'' in the question. Then the question is in MENSA range and the answer is necessarily 275.
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All comments were relevant and incisive and made me feel a lot better; THX!

I got material from another course and am using both in parallel as opposed to in series

Will comment more after I hopefully pass these exams the first time if not the first time then the second.

I m hopeful actual tests are not so devoid of contexts for certain questions
 
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