Dear AbdurRakib,

I'm happy to respond. This is a subtle and difficult question, a very good question.

First, let's consider the prompt. Suppose we are looking at some contaminant---call it X. We want to most of the X in, say, drinking water. A cleansing system that eliminates down to one part-per-thousand might leave some X at the order of parts-per-million (ppm). A more expensive system might detect and eliminate X down to 1 ppm might leave residue amounts at the order of a few parts-per-billion (ppb). You can imagine extending this process to parts-per-trillion, etc., all the time getting more and more expensive. The very best system might be so efficient that not one molecule of X is left, but it might cost $100 billion. The argument is saying: we don't necessarily need the most rigorous and most expensive system: we have to assess risk, because maybe one of the less rigorous systems would be perfectly fine.

To make the situation more clear, I will bring in a couple examples from my own knowledge. A chemical such as bleach or lye is toxic in high concentrations, but at the order of 1 part-per-thousand, it is 100% harmless. It would be complete overkill and total waste money to purifying drinking water of these chemicals beyond that level. By contrast, the neurotoxins, such as lead, are really bad: lead causes measurable neurological damage at 1 ppb, so the standards for lead are much much more stringent than they are for most other chemicals. This is outside knowledge, but it might help to give you a real world sense of the context of the problem.

OK, now let's look at the answers. What is assumed by the argument? This is essentially an assumption question. We can use the Negation Test.

A. industry currently meets the standards that have been set by environmental authorities
Not necessarily. The argument would still be valid even if industry were outdoing any standards that had been set. They may be overachieving, say, purifying down to less than 1 ppb when the official standard is 1 ppm, but it still would be unreasonable to require them to do the very best that current technology could do. We can negate this, and the argument is fine. This is not an assumption.

B. there are effective ways to take into account all of the relevant risks posed by allowing different levels of contaminants
Interesting. Suppose there were no ways to assess those risk. Suppose we had no idea whether 1 part-per-thousand or 1 ppm or 1 ppb would be safe: then would we have to use the highest possible standard, the most technologically advanced method of cleansing, regardless of the cost. This would shatter the argument. The argument depends on the fact that risk for different chemicals at different concentrations are already well known. This is a promising answer.

C. the only contaminants worth measuring are generated by industry
Some contaminate might occur naturally, or some might come from household processes or from vehicle exhaust. This could be (and is) completely false, and it doesn't change the requirement on industry. This is not an assumption.

D. it is not costly to prevent large amounts of contaminants from entering the environment
Negate this. Suppose it were quite expensive to prevent large amounts of contaminants from entering the environment. What does this mean for the argument? It's unclear. Suppose it costs an industry $1 million to remove 90% of item X. What would it cost to use the best technology, to eliminate the X completely? Maybe just another million, or maybe $100 billion. It could still be unreasonable to require the most advanced technology, so the argument still works. This is not an assumption.

E. minute amounts of some contaminants can be poisonous
Negate this. Suppose minute amounts of anything are completely safe. Then, there would be no absolutely no reason to use the most advanced technology, to eliminate even microscopic quantities, because these microscopic quantities are perfectly safe. Negating this strengthens the argument, so this choice wildly fails the negation test. This is not an assumption.

The best answer is the OA, (B).

Does all this make sense?
Mike
_________________

Type: Presuppose = Assumption
P1: In setting environmental standards for industry and others to meet, it is inadvisable to require the best results that state-of-the-art technology can achieve.
P2: Current technology is able to detect and eliminate even extremely minute amounts of contaminants, but at a cost that is exorbitant relative to the improvement achieved.
Conc: So it would be reasonable instead to set standards by taking into account all of the current and future risks involved.

Pre-think:
Diagram:
{Current tech able to detect and eliminate contaminant, but Cost > Benefit ---> Reasonable to take current and future risk}

Assume skill and/ or will (MGMAT)

Missing gap
Conc: nothing mention about KEYWORD: contaminant, Cost > Benefit

Use negation to confirm ans

The argument given concerning the reasonable way to set standards presupposes that

A. industry currently meets the standards that have been set by environmental authorities
[industry currently does not necessarily meet the standard that have been set by environmental authorities - No impact]
B. there are effective ways to take into account all of the relevant risks posed by allowing different levels of contaminants
[there are no effective ways to take into account all of the relevant risks posed by allowing different levels of contaminants - current and future risks cannot be determined, thus weaken]
C. the only contaminants worth measuring are generated by industry
[the only contaminants worth measuring are not generated by industry - No impact - even if not generated by industry current risks and future risks can be determined]
D. it is not costly to prevent large amounts of contaminants from entering the environment
[it is costly to prevent large amounts of contaminants from entering the environment - No impact on whether current and future risks can be determined]
E. minute amounts of some contaminants can be poisonous
[minute amounts of some contaminants cannot be poisonous - argument on hand needs to take into consideration current and future risks]

Please comment. Still learning. Thanks

Conclusion :- it would be reasonable instead to set standards by taking into account all of the current and future risks involved

Basically, it says that instead of measuring all the pollutants (for example), its good to know the risks and then control contaminants.

There are certain below assumptions:-
1) Risks can be measured.
2) Setting standards for contaminants is not necessarily controlling risks
3) Risks can be controlled even by not setting strict standards

A. industry currently meets the standards that have been set by environmental authorities. We don't know if standards are currently met. We ar concerend about future risks.
B. there are effective ways to take into account all of the relevant risks posed by allowing different levels of contaminants. This is one of the assumptions we derived.
C. the only contaminants worth measuring are generated by industry. It does'nt matter. It can be generated by others also. We are talking about industries only.
D. it is not costly to prevent large amounts of contaminants from entering the environment. We know that it is costly to remove contaminants from enviornment. We don't know if preventing the entry is costly or not.
E. minute amounts of some contaminants can be poisonous. We want to know about risks and not really poisoning effect.
_________________

Can someone elaborate on why E is wrong?

Conclusion : it would be reasonable instead to set standards by taking into account all of the current and future risks involved

If we're assuming that even minute amounts of contaminants can be poisonous then isn't that the basis for needing to establish any type of standards?

I was down between B and E.

Is E wrong because of the word "some". If it didn't have that and said minute amounts of contaminats can be posionous would the answer change?

loved this questions!

premise: current techs do a lot, but the cost sometimes is not reasonable verusus improvement
conclusion: it is reasonable to set standarts involving risks of present and future

B fits perfectly. To be sure, let's negate it: there are no effective ways to take into account all of the relevant risks posed by allowing different levels of contaminants. This does break the argument, fits!

Dear AnubhavK,

I'm happy to respond. :-)

For GMAT CR purposes, "presupposes" is the same as "assumes." This is another way of asking an assumption question. See:
Assumptions and the Negation Test on the GMAT
GMAT Critical Reasoning: More on Assumption Questions

The strategies discussed in those blogs will be helpful to some extent. What you really need to do to get comfortable with GMAT CR questions is to develop a habit of reading. Why do you think that a 1/3 of the GMAT Verbal questions are about arguments? Any manager or executive has to hear many arguments every single day. Fundamentally, every sales pitch is an argument. A successful executive is one who can learn a great deal from the arguments he hears, discern the flaws and what not to believe, and understand when an argument indicates that he has to change course. You get better by reading arguments and thinking about them. If you read the business news, you will find tons of arguments. Read these arguments and reflect on them. See:
How to Improve Your GMAT Verbal Score
That is really how you improve.

Does all this make sense?
Mike :-)
_________________

Thanks for replying.

What do you make of " allowing different levels of contaminants"?

Nowhere, the arguments says anything about type or level of contaminants. Moreover, last line says environmental standards should be set by considering all present and future risks, it doesn't specify risks associated with contaminants. There may be a dozen other kinds of risks involved while setting environmental standards.

Please enlighten!

I arrived at the right answer by elimination. Here, none of the other options was close. The argument is recommending that it's ok to let amounts of contaminants in the environment, provided that risk-assessment allows us to do that.

So, the pre-supposition is that it is possible to correlate the risk levels with different levels of contaminants.

Interesting and logical. B is the only option that talks about risks - it is the main reason to be the right answer.

Official Answer:

Situation State-of-the-art technology can detect and eliminate even tiny amounts of environmental contaminants, but at a cost that is exorbitant relative to its benefits.

Reasoning What must be true in order for the argument's premises to support its conclusion? The argument is that environmental standards requiring the best results that state-of-the-art technology can provide are unreasonably expensive relative to their benefits, so it would be reasonable instead to set environmental standards that take into account all present and future risks from contaminants. In order for the premise to support the conclusion, the environmental standards based on present and future risks would have to be less expensive relative to their benefits than the best results environmental standards are. Furthermore, setting the current and future risks environmental standards cannot be reasonable unless it is feasible to assess present and future risks as those standards require.



The argument does not say which standards, if any, environmental authorities have set. In any case, such standards could be reasonable or unreasonable regardless of whether industry currently meets them.



Correct. If taking future risks into account were infeasible, then applying the current and future risks standards would also be infeasible. And setting those standards would be unreasonable if they could not feasibly be applied.



According to the stimulus, the proposed current and future risks standards would apply to industry and others. So those standards could be reasonable even if the unspecified others also generated contaminants worth measuring, and even if the standards required measuring those contaminants.



Even if it were costly to prevent large amounts of contaminants from entering the environment, the benefits of doing so to prevent present and future risks might outweigh the costs.



The current and future risks standards could take into account any poisoning risks posed by minute amounts of contaminants.
_________________