Critical Reasoning

Installing scrubbers in smokestacks and switching to cleaner-burning fuel are the two methods available to Northern Power for reducing harmful emissions from its plants. Scrubbers will reduce harmful emissions more than cleaner-burning fuels will. Therefore, by installing scrubbers, Northern Power will be doing the most that can be done to reduce harmful emissions from its plants.

Which of the following is an assumption on which the argument depends?

(A) Switching to cleaner-burning fuel will not be more expensive than installing scrubbers.
(B) Northern Power can choose from among various kinds of scrubbers, some of which are more effective than others.
(C) Northern Power is not necessarily committed to reducing harmful emissions from its plants.
(D) Harmful emissions from Northern Power's plants cannot be reduced more by using both methods together than by the installation of scrubbers alone.
(E) Aside from harmful emissions from the smokestacks of its plants, the activities of Northern Power do not cause significant air pollution.


































OA is D. I agree. But why B is wrong? I think B is also an assumption. Because if Northern Power cannot choose the most efficient scrubbers, how can it do the most to reduce the pollution??

Can anyone help me?

Assumption fills the logical gap.

Premises: 2 ideas for less harmful emission. 1 is more effective than other.
Assumption:?
Conclusion: Most can be achieved from 1.

It cannot be B because:
Nothing mentioned about kinds of scrubber. This situation of choosing from different scrubbers arises only after there is a decision to use ONLY scrubbers not cleaner fuel. This statement logically happens after the argument is established in this context.

Thanks shovan.

But I still don't understand.

Because the conclusion of this argument concerns whether the city can remove the pollution MOSTLY, we should assume that the city can choose the most efficient scrubbers from a lot of scrubbers.

Can anyone help me find where I get wrong????

Hi Guys, I completely understand that the OA is B
However, I am really confused with option E. Could someone please help ?

rx_11 wrote:Installing scrubbers in smokestacks and switching to cleaner-burning fuel are the two methods available to Northern Power for reducing harmful emissions from its plants. Scrubbers will reduce harmful emissions more than cleaner-burning fuels will. Therefore, by installing scrubbers, Northern Power will be doing the most that can be done to reduce harmful emissions from its plants.

Which of the following is an assumption on which the argument depends?

(A) Switching to cleaner-burning fuel will not be more expensive than installing scrubbers.
(B) Northern Power can choose from among various kinds of scrubbers, some of which are more effective than others.
(C) Northern Power is not necessarily committed to reducing harmful emissions from its plants.
(D) Harmful emissions from Northern Power's plants cannot be reduced more by using both methods together than by the installation of scrubbers alone.
(E) Aside from harmful emissions from the smokestacks of its plants, the activities of Northern Power do not cause significant air pollution.


































OA is D. I agree. But why B is wrong? I think B is also an assumption. Because if Northern Power cannot choose the most efficient scrubbers, how can it do the most to reduce the pollution??

Can anyone help me?

Dani@MasterGMAT wrote:

rx_11 wrote:Thanks shovan.

But I still don't understand.

Because the conclusion of this argument concerns whether the city can remove the pollution MOSTLY, we should assume that the city can choose the most efficient scrubbers from a lot of scrubbers.

Can anyone help me find where I get wrong????

The problem is that B also introduces a new premise not included in the original argument, while D directly attacks the argument as is, or at most uses the same premises in a different way without giving any new premises. The conclusion uses "by installing scrubbers, northern power will be doing the most that can be done". In order to reach this conclusion, northern power is assuming that there is no alternative to "installing scrubbers" that achieves better results. The discussion is based around "scrubbers" Vs. outside alternatives - I don't have to assume that I choose the best "scrubbers option", as the argument as is already indicates that scrubbers are better than the other option.

If the question stem had indicated that some scrubbers provide poorer reduction than cleaner fuels, but still reach the conclusion that scrubbers are better, then I can see B as an assumption - in order to still reach the conclusion that scrubbers are better than other alternatives, I would indeed need to assume that I can choose the better scrubbers to eliminate the chance of disproving my conclusion. But as is, EVEN if B is wrong and the company doesn't choose the best scrubber, it is still doing the most it can do under the premises given in the argument - those premises comparing scrubbers to fuels.

Thanks...I finally understand...(crying...lol)...The key is by installing scrubbers...

thanks, Dani. that's a thorough explanation for B! basically, we're, in a way, assuming that the worst scrubber is still better than the best cleaner-burning fuel. thus, it (B) becomes irrelevant whether we choose the best or the worst of available scrubbers.

Installing scrubbers in smokestacks and switching to cleaner-burning fuel are the two methods available to Northern Power for reducing harmful emissions from its plants. Scrubbers will reduce harmful emissions more than cleaner-burning fuels will. Therefore, by installing scrubbers, Northern Power will be doing the most that can be done to reduce harmful emissions from its plants.

Which of the following is an assumption on which the argument depends?

(A) Switching to cleaner-burning fuel will not be more expensive than installing scrubbers.
-> out of context. Cost is not the deciding factor.
(B) Northern Power can choose from among various kinds of scrubbers, some of which are more effective than others.
-> out of context. Why only scrubbers are useful than using clean fuel.
(C) Northern Power is not necessarily committed to reducing harmful emissions from its plants.[/color]
-> Out of context. Whole argument is made to reduce harmful emission.
(D) Harmful emissions from Northern Power's plants cannot be reduced more by using both methods together than by the installation of scrubbers alone.
-> Correct assumption. Using both methods will not be useful, hence we are using scrubbers. Even clean fuel have at least some harmful emission and srubber will not be present.
(E) Aside from harmful emissions from the smokestacks of its plants, the activities of Northern Power do not cause significant air pollution.
->out of context.