i understand why the right answer is right, but i am not sure if i am buying the logic above.

how is E irrelevant to the issue? the issue is the increased frequency of serious crimes committed by local teenagers. the argument states that the measures enacted by the gov are unlikely to be succesfull because most crimes are committed btw 3-6pm. clearly the measure enacted by the gov. is a subpar solution since most crimes are committed in the afternoon. if there was another measure enacted that would help bridge the gap and keep teens out of trouble, the argument would be weakened.

George, this is a complicated argument because we are weakening the idea that something won't work (kind of a double negative). Let's review the argument:

"Citizens of parktown are worried by the increased frequency of serious crimes committed by local teenagers. In response, the city government has instituted a series of measures designed to keep teenagers at home in the late evening. Even if the measures succeed in keeping teenagers at home, however, they are unlikely to affect the problem that concerns citizens, since most crimes committed by local teenagers take place between 3pm and 6pm."

Let's pick out the conclusion, premise, and assumptions. Italics below are mine but help emphasize what you should look for in arguments--change in wording!

Conclusion: Late evening curfew won't reduce serious crimes committed by teenagers.
WHY?
Premise: Most crimes committed by teenagers occur between 3-6pm.
Assumption: Many of the crimes committed during 3-6pm are serious crimes.

We want to weaken this conclusion, and say that the curfew WILL in fact reduce the number of serious crimes committed by teenagers. Generally to weaken a conclusion we want to attack the assumption. Notice how answer choice B does this nicely.

Your answer choice, E, says that teenagers will now have something to do after school. This doesn't help us establish that the curfew WILL in fact reduce crimes, since after school is a different time of the day from the curfew. Make sense?

_________________
Jamie Nelson
ManhattanGMAT Instructor

Wow. This is has come to be the best CR question so far.

Have a confusion in choice D:

D) Any decrease in the need for police patrols in late evening would not mean that there could be more intensive patrolling in the afternoon.

Do we need to have an extra assumption with this choice viz. police patrolling will be effective to reduce crimes. Or is there any other reason for rejecting this choice ?

Thanks,

the point of the argument is that the new rules will be “unlikely to affect the problem”.
choice (d) strengthens this argument, by giving an additional reason why the new rules will have no affect on the afternoon situation. you want a choice that weakens the argument, so choice (d) is totally backward.

Paraphrasing: most crimes are in afternoon, so keeping the teen at home in the evening dose not help
Prethinking: Assumption: there is no other cause, the aswer: there is another cause which make keeping still good
Look for a match: B is most close the the direction prephrased.

I see that though the prethinking can not make us find a close match in answer choices, it make us in the right direction.

good stuff..

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Tim Sanders
Manhattan GMAT Instructor