Q12 - Photovoltaic power plants produce electricity

[wayne_palmer10]

Based on the question stem, this is a sufficient assumption question. I had trouble with the answer choices. All of them seemed so similar with the terminology and with the way that they were presented. How would you go about solving this problem? Thanks!

[rsmorale]

I'd appreciate some insight into this question.

Premises: Due to tech advances, the cost for producing electric power (at Photovoltaic plants) is 1/10 of what it was 20 years ago;
+
The corresponding cost for producing electric power (at Traditional plants) has increased.

Conclusion: Photovoltaic plants offer a LESS expensive approach to meeting demand for electricity than do traditional power plants.


(A) A is a Premise booster - we already know this about traditional plants
(B) The stimulus shows no numerical proof to establish an exact figure such as "10 times more power"
(C) I liked this one. Help?
(D) No clue as to why this is the credited response.
(E) This is unsupported - we have no way of knowing what is to happen in the future.

Appreciate the help!

[noah]

Alright! Let's take a look at the core:

solar plants now 1/10 of what they cost 20 years ago + oil plants getting costlier --> solar plants are less expensive than oil plants

(note that I'm using "oil" for traditional - we've got to move fast, the clock is a-ticking!).

Gap: It's clear that solar is cheaper than it used to be, but is it cheaper than oil now? It might still be more expensive - we'd have to assume that it was really more expensive 20 years ago.

(D) covers this gap - if 20 years ago the plants were less than 10 times the cost of the oil ones, cutting the solar cost to a tenth of what it was would make it cheaper than oil was then (and since oil's cost is increasing, we know that this would be cheaper than today's prices). To give a numerical example of what this answer ensures:

1990: solar = $99 & oil = $10 (so, solar $ is less than 10 times oil $)
2010: solar $9.90 & oil = $10.10 (yes, solar is cheaper!)

As for the incorrect answers:

(A) is a premise booster

(B) is out of scope - we're not discussing how much power, but how expensive that power is.

(C) is tempting, but irrelevant. (C) tells us that the solar advances are inapplicable to oil plants - but how does this affect pricing? Couldn't there be other advances for the oil plants? If you liked this answer, you must have been doing a lot of "work" to make it correct.

(E) is also tempting, but are these expected decreases enough to overcome the potentially huge initial expense of solar power? We need to know more specific numbers, like (D) provides. The decrease mentioned here might be just pennies. Come on, (E), you can do better than that!

[rsmorale]

This is super helpful, Noah. Thanks! I'm gonna try assigning numerical figures to these in my practice and see if I can make it intuitive over the next month!

[WaltGrace1983]

(E) is also tempting, but are these expected decreases enough to overcome the potentially huge initial expense of solar power? We need to know more specific numbers, like (D) provides. The decrease mentioned here might be just pennies. Come on, (E), you can do better than that!

Thanks Noah! I really liked how simple your explanation was. However, I have something to add. The conclusion is talking about what is going on now. There is no indication that the conclusion is discussing anything in the future it just says that these solar plants "offer a less expensive approach" because they "are" 10% of the cost 20 years ago. Thus, why do we care about what is going on in the future? Maybe tomorrow the price of solar plants will rise dramatically and it will be 50 billion times more expensive than traditional plants. Does this hurt our conclusion? I don't think so because the conclusion is focused in the present.

The conclusion probably likes yoga It sees out of its third eye and focuses on being mindful of the here and now.

(gotta make studying fun, right?)