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PT 51, S1, Q20 - Only experienced salespeople will be able

by dj_grey Tue Feb 02, 2010 7:47 am

I got this wrong. I did the problem again.......still got it wrong. The answer is B but i thought the best answer was "C". COuld someone explain the logic that i must be missing.
 
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Re: PT 51, S1, Q20 - Only experienced salespeople will be able

by dj_grey Tue Feb 02, 2010 7:53 am

I think i just figured it out......but wanted confirmation.

B and C are very similar in their statements. However, in the argument there is a wording of "I must not count". If you look at "C" the wording is "may expect" which is not like the wording of the argument. However, "B" has wording like "not taking classes" which is more like the original statement. Thus, B is the right answer.
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Re: PT 51, S1, Q20 - Only experienced salespeople will be able

by noah Tue Feb 02, 2010 12:39 pm

You're right to look for shifts in the way things are phrased (i.e. "many" vs. "all"), but (C) is primarily wrong for a different reason. Let's start by identifying the flaw in the original argument:

In brief, the argument is that only experienced salespeople will make their quota, thus I'm not experienced since I didn't make the quota.

The problem with this is that you may be experienced but NOT make the quota. What you do know is that if someone does make the quote, they are experienced.

[This would be like saying: Only those over 15 years old can be on the gymnastics team. Since I'm not on the gymnastics team, I must not be over 15 years old. Maybe I'm 14 but just not into wearing tights. ]

Diagrammatically, the argument says this:

make quota --> experienced
not make quota --> not experienced

boiling it down further:

q --> e
~ q --> ~ e

As you can see, this is a simple negation (which of course is a no-go in logic), not the contrapositive.

(B) has the same structure:

take class --> music lover
~ take class --> ~ music lover

The other answers are wrong for various reasons that all boil down to not matching the argument's flaw.

(A) casually dressed --> Friday
~ casually dressed --> Not going to work

This introduces some new elements to the argument. It should conclude that it's not Friday.

(C) enjoy the Atlantic --> oceanographer
~ oceanographer --> ~ enjoy the Atlantic

A-ha! This is a valid argument. It uses the contrapositive.

(D) giant redwood --> northern
redwood --> northern

Again, a valid argument. This one utilizes a simple application of the premise.

(E) El Capitan --> accomplished climber
accomplished --> El Capitan

This is an illegal reversal, not a negation. Being accomplished is a requirement for being able to climb El Capitan, but it's not sufficient for being able to do so. To "make" this one parallel, it should say "since she cannot climb El Capitan, Michelle must not be accomplished."
 
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Re: PT 51, S1, Q20 - Only experienced salespeople will be able

by dj_grey Tue Feb 02, 2010 4:23 pm

Your summary is very good! I understand now.......thank you very much!
 
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Re: PT 51, S1, Q20 - Only experienced salespeople will be able

by dj_grey Tue Feb 02, 2010 4:28 pm

In reviewing your answer and then re-reading the problem i had a question.

The first sentence as you stated goes something like.......
"experienced salespeople make quota". Then the 2nd sentence something like "since i am not experienced i wont make quota".

So shouldnt the diagram be
e > q
~e > ~q

Why did you put as the diagram
q > e
~q > ~e

I understand everything you did except why your diagram is not
e > q
~e > ~q
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Re: PT 51, S1, Q20 - Only experienced salespeople will be able

by noah Tue Feb 02, 2010 5:21 pm

Yeah -- tricky wording. Let's use this as an analogy:

Only NYC rats will be able to escape from cats. Thus, that rat must not be a NYC rat since the cat caught it.

This has the same structure.

The first sentence - Only NYC rats will be able to escape from cats. - boils down to
Run away --> NYC rat

The issue is, is being a rat necessary if you run away from a cat, or it is necessary that you run away from cats if you're a NYC rat? It's the former. Even NYC rats will get caught from time to time, but if you see a rat get away, it must be a NYC rat!

The second sentence - Thus, that rat must not be a NYC rat since the cat caught it. - boils down to
~escape (caught) --> ~ NYC rat

Here, the easiest thing to latch on to is the "since". That word indicates that we're dealing with the sufficient side of the logic, or the "trigger".

Now, go back and look at the argument -- tell me what you think. BTW, it looks like you need to read up a bit on your conditional logic. If you have our books, look at chapter 7 of the Logical Reasoning strategy guide.
 
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Re: PT 51, S1, Q20 - Only experienced salespeople will be able

by dj_grey Tue Feb 02, 2010 8:43 pm

i wish i had found this site much earlier. If i had i would have purchased a book and some tutoring.......but i think its too late now. But i like your explanations. And if know of anyone planning to take the LSAT i will be sure to recommend this site and/or your course/books.