Engineer: Thermophotovoltaic generators are devices that convert heat into electricity. The process of manufacturing...

Naz on September 16, 2014

Here we have a strengthen with necessary premise question. Remember that a premise is necessary for a conclusion if the falsity of the premise guarantees or brings about the falsity of the conclusion. First we check to see if the answer choice strengthens the passage, and then, if it does strengthen, we negate the answer choice to see if its negation makes the argument fall apart. If the answer choice does both those things then it is our correct answer.

Our conclusion is "if steel-manufacturing plants could feed the heat they produce into thermophotovaltaic generators, they would greatly reduce their electric bills, thereby saving money."

Why? Because thermophotovoltaic generators are devices that convert heat into electricity, and the process of manufacturing steel makes a large amount of heat that is currently being wasted.

Answer choice (C) states: "The amount steel-manufacturing plants would save on their electric bills by feeding heat into thermophotovoltaic generators would be sufficient to cover the cost of purchasing and installing those generators."

Does this answer choice strengthen the argument? Yes. If the money that the steel-manufacturing plants are going to save on their electric bills covers the cost of purchasing and installing one of the generators that will be converting the heat to electricity, then the steel-manufacturing plants will, in fact, save money on their electricity bills.

For example, if the cost of the generator and its installation was $700 and the plant eventually saves $2000 on their electricity bill, then they have saved $1300 by investing in the generators.

Does the negation of the answer choice make the argument fall apart? Yes. Negation: The amount steel-manufacturing plants would save on their electric bills by feeding heat into thermophotovoltaic generators would not necessarily be sufficient to cover the cost of purchasing and installing those generators.

If the amount that is going to be saved on the electric bills does not cover the cost of purchasing and installing the generator, then the steel-manufacturing plants would not actually be saving any money, would they? For instance, if in the long run the plants only save $100 on their electric bills due to the generators, but the cost and installation of the generators reached upwards of $700, then the plants have lost $600. Do you see?

So, if we negate this answer choice, the argument falls apart because the plant would no longer necessarily be saving any money.

Hope that helps! Please let us know if you have any other questions.

kens on September 5, 2020

would "not necessarily" in this case indicate that it could, but it might not? If so, how does the negation destroy the conclusion? Thanks in advance!

ScienceMathTutor on September 19, 2021

I feel like answer C is out of scope as we don't explicitly know the costs involved.

ScienceMathTutor on September 19, 2021

And we are to assume that saving money on electric bills is equivalent to "saving money overall". Seems like they want us to assume things here that are simply not reasonable to assume.

ScienceMathTutor on September 19, 2021

Answer C does not say anything about the cost of running the generators on a monthly basis. Only the cost of purchasing and installing which are initial costs NOT related to an electric bill?

Ravi on February 5, 2022

@ScienceMathTutor, it's not out of scope because we need for this endeavor to produce a net gain in savings in electricity. This means that the device has to save enough money to offset any costs involved with the installation and use of the thermophotovoltaic generator. This is why C must be correct if this argument is going to stand any chance of making sense.

v.h on February 5 at 11:33PM

I hesitated to put C because I don't think that installation costs and purchasing costs are the only costs to consider (i.e maintenance). So I do not think that purchasing costs and installation costs alone are necessary for the conclusion.

Emil-Kunkin on February 8 at 09:12PM

You're right that these are not the only costs. However I think you might be approaching this as if it were a sufficient assumption question- where we need to fix the gap and make the argument correct. Here our job is only to to find what the author must believe. The author must believe that the benefit would be great enough to cover some of the necessary costs. Just because there may be additional costs does not undermine the fact that the author must think we are able to cover these specific costs. If the author thought we were unable to cover these two costs, the argument falls apart.