## A Pair of Games

Prepare for the LSAT or discuss it with others in this forum.
Manhattan LSAT Noah

Posts: 744
Joined: Tue Oct 12, 2010 8:43 am

### A Pair of Games

We've written a couple of games - a hard and simple version to explore how the LSAT messes with standard forms. Have fun! http://www.manhattanlsat.com/logic-games-practice.cfm

Big Disclaimer since TLS is a tough crowd: NOT that you should do fake logic games in the place of real ones (and it's always great to do games over and over again), but if you've done them all...

Jeffort

Posts: 1888
Joined: Wed Jun 18, 2008 4:43 pm

### Re: A Pair of Games

On first read I expected that 'walk into a bar' was going to complete the thread title!

/just saying

Manhattan LSAT Noah

Posts: 744
Joined: Tue Oct 12, 2010 8:43 am

### Re: A Pair of Games

Alright, who's got the joke figured out? All I can think of are dirty ones about ordering, and that wouldn't befit the LSAT...

TJISMYHERO

Posts: 291
Joined: Thu Aug 05, 2010 1:14 pm

### Re: A Pair of Games

Fixed already. Fun game, I can see these being worthwhile if someone were out of actual games to play.

Manhattan LSAT Noah

Posts: 744
Joined: Tue Oct 12, 2010 8:43 am

### Re: A Pair of Games

Phew - I was working hard to figure out if that was the "a pair of games walks into a bar" joke. Yeah, for a few hours, the site was showing questions for both the easy and hard version - that's not a twist you'll see on the LSAT!

Kurst

Posts: 446
Joined: Mon Aug 09, 2010 9:33 pm

### Re: A Pair of Games

Thanks for posting another game, Noah! These are always fun.

If I am not mistaken, the seventh question of the hard version has three correct answer choices: B, C, and D.

7. Which of the following, if substituted for the rule that P presents after L if and only if P does not present after M, would have the same impact on determining the order of presentations?

The original rule:

L-P <--> P-M
Contrapositive: M-P <--> P-L

From the original rule, there are two possible arrangements of L, P, and M: L-P-M or M-P-L.

Answer choices B, C, and D all appear to create this same dichotomy.

(B) If L is before P, P is before M.
L-P -> P-M (L-P-M)
M-P -> P-L (M-P-L)

(C) If P is after M, L is after P.
M-P -> P-L (M-P-L)
L-P -> P-M (L-P-M)

(D) Either L or M, but not both, is before P.
M-P-L
L-P-M

Cambridge LSAT

Posts: 257
Joined: Mon Aug 24, 2009 3:26 pm

### Re: A Pair of Games

Kurst wrote:From the original rule, there are two possible arrangements of L, P, and M: L-P-M or M-P-L.

Answer choices B, C, and D all appear to create this same dichotomy.

(B) If L is before P, P is before M.
L-P -> P-M (L-P-M)
M-P -> P-L (M-P-L)

(C) If P is after M, L is after P.
M-P -> P-L (M-P-L)
L-P -> P-M (L-P-M)

Choices B and C are incorrect for the same reason. You've neglected the third possibility for each choice: that in which neither the replacement condition nor its contrapositive is triggered. Note that choices B and C are actually contrapositives of each other, and are logically equivalent. Each one allows for the possibility that P is before both L and M. Thus, neither choice is a perfect replacement for the original condition.