CR_Support

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CR_Support

by Soumita » Sun Jan 06, 2013 2:29 pm
A greater number of cars are sold in Town P than in Town Q. Therefore, the citizens of Town P spend more time driving their cars, per capita, than do the citizens of Town Q.

Each of the following, if true, weakens the conclusion above EXCEPT:
A.Town P has a larger population than Town Q.
B.Most citizens of Town Q work in Town P and buy their cars there.
C.Many residents of Town P purchase second cars that they use only rarely.
D.Most drivers from Town P tend to drive only during the day, and only within the city limits of TownP.
E.The average price of cars sold in Town P is lower than the average price of cars sold in Town Q.

Can anyone explain me the answer..I am not finding any of the choices correct.

According to my understanding of the argument the number of cars sold in town P is more than the number of cars sold in town Q as people in town P spent more time in driving than people in town Q.

Premise : the number of cars sold in town P is more than the number of cars sold in town Q

Conclusion : people in town P spent more time in driving than people in town Q

We have to find choices which support the conclusion.

A)Town P has a larger population than Town Q:- there is more sale of car in town P not due to time but due to higher population in town P.This weaken the conclusion instead of support. Not Correct.

B)Most citizens of Town Q work in Town P and buy their cars there:- so there is more sale in town P than town Q. Therefore not for time there is more sale in town P than town Q.This weaken the conclusion instead of support. Not Correct.

c)Many residents of Town P purchase second cars that they use only rarely.:- so people in town P do not spent much time in driving.This weaken the conclusion instead of support. Not Correct.

D)Most drivers from Town P tend to drive only during the day, and only within the city limits of TownP.:- so town P spends less time in driving.This weaken the conclusion instead of support. Not Correct.

E)The average price of cars sold in Town P is lower than the average price of cars sold in Town Q.:- town p people buy more number of car than town Q as the average price of car in town P is less than the average price of car in town Q. So not for more time spent by people in town P than people in town Q. This weaken the conclusion instead of support. Not Correct.
Source: — Critical Reasoning |

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by ceilidh.erickson » Tue Jan 08, 2013 1:55 pm
It's natural to assume that "each of the following weakens EXCEPT" means the same thing as "which of the following strengthens?" But be careful! This is not necessarily the case on the GMAT. In fact, more often than not with EXCEPT questions, you'll get 4 that weaken, and 1 that's simply irrelevant. Don't focus on finding one that strengthens. Find 4 that weaken, and the one that doesn't weaken will be your answer.

To look for answer choices that weaken the conclusion, we have to ask ourselves - what logical gaps are there in the argument?

Premise : the number of cars sold in town P is greater than the number of cars sold in town Q

Conclusion : people in town P spent more time in driving than people in town Q

Logical gaps: How does total number of cars sold relate to driving per capita?
- Are there the same number of people in each town?
- Does each car owner spend the same amount of time driving each car?
- Do people only buy cars in the town they live/drive in?

Your logic in breaking down the answer choices was largely correct:

(A) If the populations aren't comparable, then we can't compare number of cars total to per capita driving. WEAKEN

(B) The town in which the cars are purchased is not indicative of the town in which they're driven. WEAKEN

(C) Time spent driving is less per car in Town P. WEAKEN

(D) Town P drives for shorter distances, and thus presumably for less time. WEAKEN

(E) Be careful with this one. Does this actually undermine the idea that people in Town P drive more? It doesn't actually speak to a logical gap in the argument. The fact that cars are cheaper in Town P would explain why more cars are purchased there, but it has no connection to how much people are driving, or where. It explains the premise, but doesn't undermine the conclusion. IRRELEVANT

Thus, the only answer choice that doesn't weaken the argument is E.
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Harvard Graduate School of Education

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by Soumita » Tue Jan 08, 2013 7:53 pm
Thanks a lot for your response.

I understand your instruction that I have to find the the choice which does not weaken the argument i.e irrelevant.

Choice E)The average price of cars sold in Town P is lower than the average price of cars sold in Town Q.:- town p people buy more number of car than town Q as the average price of car in town P is less than the average price of car in town Q. So not for more time spent by people in town P than people in town Q. This weaken the conclusion. it is correct

I am not understanding how this choice is irrelevant??

Please explain me.

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by ceilidh.erickson » Wed Jan 09, 2013 12:20 pm
If I'm understanding you correctly, you're saying that E basically says "citizens of Town P buy more cars because the price is lower, and not because they drive more... so this weakens."

Be careful, though! You don't want to add any of your own assumptions. Given that the price of cars in Town P is lower... I think that your analysis is partially correct - this statement implies that there might not be a direct correlation between amount of driving done and number of cars bought, because there could be an alternative explanation for why cars are bought. However, the conclusion that you're trying to weaken is not "there is a direct correlation between amount of driving and number of cars," but rather, "citizens of Town P spend more time driving."

Does the fact that cars are cheaper in Town P mean that they definitely aren't driving as much? Not necessarily! It could be the case that cars are cheaper and people drive more. We just don't know anything about per capita driving from this statement.

So, E is not irrelevant to the argument - it disrupt the assumed causal structure: more driving -> more cars bought. However, it does not actually weaken the stated conclusion about amount of driving, so it's irrelevant in that regard.

Did that help to clarify?
Ceilidh Erickson
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Harvard Graduate School of Education