Exterminator: Using poisoned food is the most effective tactic for com

+1 for C.



Weakener :
What if the mouse does not return back to its nest soon enough to "cause all of the mice to die", that way the plan may fail miserably.

(C) In the spring, many mice that nest in houses begin foraging for food outside and do not return to the comfort of the house until the fall or winter. --> Correct, matches our pre-thinking

Hence, C.
_________________

broall , VeritasKarishma , gmatexam439

Why is A incorrect?. If mice hide whenever they sense humans and it is very difficult to see or hear mice, why can't it be a weakener?

The stem says



A) talks about only to see or hear the mice of disappearing. We need that all the signs are gone such as food rests, droppings and so forth.

Moreover, in general, mice are always difficult to see or hear. So A) is wrong for these reasons.

Hope now is clear
_________________

This question is from GRE Practice Problems. The explanation the book has is:

6. (C). The exterminator explains the effects of using poisoned food to combat a mouse infestation: mice will pick up the food an carry it to the nest, where all of the mice will eat the food and die as a result. The exterminator then claims that if X happens, then it will be certain that Y happened first. Specifically, he claims that if all signs of the mice disappear for three consecutive weeks after setting out poisoned food, then the mice all must have died as a result of that poisoned food. The correct answer will weaken this claim, for instance by showing that if X happens, it will not necessarily mean that Y happened; perhaps there is another reason why happens.

(A): this choice is very tempting, but the exterminator argues that "all signs" of the mice "disappear"; this choice mentions only the difficulty of seeing and hearing mice. These do not represent "all signs" of an infestation; mice may leave dropping, chew things up, and so forth. Further, the mice are not harder to see and hear only after poison has been used. They are always hard to see and hear, so this does not provide an alternative explanation as to why signs might diminish or disappear after poison has been used.

(B): this choice may be true, but it does not address the exterminator's claim that if all signs disappear, then the poison must have killed the mice.

(C): CORRECT. This choice offers an alternative explanation for absence of signs of an infestation. If the mice have left the house, then any signs of infestation would also cease because the mice are no longer there. However, the signs will have ceased because the mice left voluntary, not because they have been eradicated by the poison, as claimed by the exterminator.

(D): it is likely true that different poisons have different levels of efficacy, but this argument does not distinguish between types of poison. The claim is simply that the poison must have killed the mice (as opposed to some other explanation for why the signs of the mice would disappear).

(E): The exterminator does not claim that the poison will work within three weeks (or within any time frame at all). He only claims that if the signs disappear over three consecutive weeks, then that means that the poison worked. It might be the case that the signs don't disappear until weeks 3, 4, or 5, but the exterminator's claim would still hold: because the signs have disappeared for three consecutive weeks, the poison worked.

Hi Lakshya

In such problems where we are asked to weaken an unqualified conclusion, it is enough to provide one scenario where the conclusion does not hold. That such a scenario might not always occur does not mean that it is not a valid weakener.

In this stimulus, there is an unqualified conclusion being made.

If all signs of the mice disappear for three consecutive weeks after poisoned food is used, the homeowner can be sure that the poison was successful in eradicating the mice.

This is interpreted to mean that under all scenarios and circumstances, if there are no signs of mice for three weeks, then the problem has been eradicated. In order to weaken this, it is enough to provide one scenario, which may only hold true at some times and not at others, where absence of ice for three weeks does not necessarily mean eradication of the problem. Option (C) does that clearly, and hence is a valid weakener of the conclusion.

Obviously, if it is not spring or summer, then this does not act as a weakener. However, since the conclusion does not state that the absence of mice for three weeks indicates eradication of the problem only in fall or winter, option (C) is a valid weakener.

Hope this helps.
_________________

This is a clear cause effect question
Cause - Effect
Poisoned food (c)- mice eradication (Not present for 3 w) (e)
To weaken this we need to show that something else caused the mice not be in the house for >3 W
Option c clearly tells us that

CrackverbalGMAT KarishmaB why not E?

you have to select an answer which clearly undermines the statement. Option C does the job with absolute perfection.

Option E uses "sometimes". Not a solid answer.
_________________

GMATking94 pls elaborate further in detail. What role will it have with sometimes and the other errors associated with that chocie besides sometimes.

Would it be correct if it said 'all the time'?

Elite097

If you ask the question what would have been the case if it said "all the time" then there might be other changes in other options. GMAT questions always point towards a specific options based on the logic that is being tested. Please be careful to select the best answer always not the perfect answer. Here E fails clearly when compared to C. Hence, C is the correct choice.
_________________

GMATking94 KarishmaB why does E fail here and how does the word “sometimes” make E worth eliminating . Pls elaborate both cases of “sometimes”

It might be the case that the signs don't disappear until weeks 3, 4, or 5, then how will the exterminators claim still hold?

Posted from my mobile device

Elite097

I would again emphasize you to think on the options.

Option E do not provide a concrete reason to doubt the claim. It simply says it might take more than 3 weeks to ingest and die from the poison.

Now think what is the main point of the question -

If all signs of the mice disappear for three consecutive weeks after poisoned food is used, the homeowner can be sure that the poison was successful in eradicating the mice.

Does E helps in any way???

Now what does C says -



so, it clearly undermines the fact by stating that the disappearance of the mice is for other reasons and not due to it being eradicated by poison.

I hope it helps.
_________________