Difficulty in scenario set up in Preptest 52, 4th logic game

secretad
Posts: 209
Joined: Tue Jan 04, 2011 11:26 pm

Difficulty in scenario set up in Preptest 52, 4th logic game

Postby secretad » Wed Apr 13, 2011 9:30 pm

There are two scenarios that can play out due to the conditional rules.

A world with F>M ---> L>H

And a world with H>L ---> M>F

The last constraint gave us either M> H & K
or H & K > M because M cannot go between the two variables.

So, I then decided to make my two hypothetical scenarios and I notice that the second scenario seems to be incorrect because the answer to #20 is not B, which I selected without giving it a second thought because of the inference work I did.

Tell me how is the second scenario invalid, or how 20 is not B.

Image

User avatar
510Chicken
Posts: 88
Joined: Sat Jan 15, 2011 5:50 pm

Re: Difficulty in scenario set up in Preptest 52, 4th logic game

Postby 510Chicken » Thu Apr 14, 2011 12:06 am

Your diagram is wrong. I'm fairly certain that there are more than two setups to an unconstrained scenario. In particular, you diagrammed a false contrapositive of rule 3. (F > M --> L > H) does not mean (M > F --> H > L) as you have in scenario 2. You're missing (M > F , L > H). Also, rule 3 does not react in overly restrictive ways with rule 4, which means that there are a bunch of permutations that you don't have. Not that you need them.

The correct interactions for 20 are included below.

--ImageRemoved-- (LinkRemoved)

K must be last. Everything else comes before it except for L, but L is given to be 3rd. As you can see, H does not need to precede L. M must precede H. So (E).

secretad
Posts: 209
Joined: Tue Jan 04, 2011 11:26 pm

Re: Difficulty in scenario set up in Preptest 52, 4th logic game

Postby secretad » Fri Apr 15, 2011 11:22 am

Yeah my bad on that. I don't know why I made that faulty "inference"

We know what happens when F>M, but we do not know anything about M>F.

I reworked the game and it went much better.

I would like to ask a general question on conditional sequencing games because these games, while workable, take so much of my time. They are not necessarily difficult, just time consuming.

I feel as if sometimes I am missing a big deduction. What can one do with conditionals with some straight sequencing rules such as this game?

I assume the only time I can infer something is if I am given two conditionals such as M>F -> something

and F>M -> something. That would give me all of the logical world to work with and could then tie in the straight sequencing rules if they given.

Am I correct in this thinking? And is there any other time when one could infer something, like would an if and only if be unique at all in making deductions?




Return to “LSAT Prep and Discussion Forum”

Who is online

Users browsing this forum: dontsaywhatyoumean, galeatus and 4 guests