Peculiar CR from LSAT

[abedinbhuiyan]

Only an expert in some branch of psychology could understand why Patrick is behaving irrationally. But no expert is certain of being able to solve someone else’s problem. Patrick wants to devise a solution to his own behavioral problem.
Which one of the following conclusions can be validly drawn from the passage?
(A) Patrick does not understand why he is behaving in this way.
(B) Patrick is not an expert in psychology.
(C) Patrick is not certain of being able to devise a solution to his own behavioral problem.
(D) Unless Charles is an expert in some branch of psychology, Charles should not offer a solution to Patrick’s behavioral problem.
(E) If Charles is certain of being able to solve Patrick’s behavioral problem, then Charles does not understand why Patrick is behaving in this way.


What is the answer??

[tim]

Don't expect any help from MGMAT instructors with LSAT questions. It's the equivalent of posting a question that says "can you help me with this organic chemistry question". Seriously. They're that different. The LSAT does not have a CR section, and one of the biggest disservices students can do for themselves is to try to use LSAT questions to study for the GMAT. They ARE NOT THE SAME!!!!!!

[abedinbhuiyan]

I think u can help me. Do u think LSAT Critical Reasoning will help me for GMAT Critical Rreasoning? In-fact I am confused.

BR

[tim]

Perhaps you did not read my previous post. Don't study LSAT questions to prepare for the GMAT. You might as well be studying Lady Gaga lyrics for all the good it will do you..

[aidanmenzul]

I actually think studying LSAT Preptests was pretty conducive for me. Reasoning is reasoning but the section is much more important on the LSAT so it's more difficult, but if you're only missing under 5 on the LSAT LR you should be in good position to get a perfect score on GMAT CR.

Anyway to answer your question, it's (E).

The 1st premise is that

To understand why Patrick is behaving irrationally, ONE MUST BE an expert in some branch of psychology. "Only" makes being an expert a necessary condition.

UP ==> E

2nd premise

No expert is certain of being able to solve someone else's problem. Now the expert becomes the sufficient condition and the necessary is the logical negative of "being certain of being able to solve someone else's problem" which is NOT being certain of "..."

E ==> -(CSP)

Conclusion

The last sentence services no purpose.
Since in order to understand why Patrick is behaving irrationally you MUST BE an expert, it follows that IF someone that understands why he's behaving irrationally, then that person is not certain of being able to solve someone else's problem. That's essentially what E says except they add this Charles person to throw you of.

UP ==> E ==> -(CSP)
UP ==> -(CSP)

The answer just words it as a contrapositive CSP ==> -(UP)

[abedinbhuiyan]

Gr8T!!!

[tim]

Glad to see our students helping each other out. I do agree with Aidan that reasoning is reasoning, and I would never discourage someone from spending their free time studying LSAT questions because they are fun and will help improve your overall thinking skill. Of course, the same is true for studying organic chemistry or doing a true literary analysis of Lady Gaga lyrics. :) Just remember that your return on investment from such random tasks is going to be much smaller if your specific goal is to improve on the GMAT..