Feb. 1999 Games#2

[sg7007]

If somebody explains this to me, I would really appreciate it.

The fourth condition says "If it is not the case that the park contains both laurels and oaks, then it contains firs and spruces."

I diagramed it as 'NOT laurels AND NOT oaks -> firs AND spruces'
The contrapositive might be 'NOT firs OR NOT spruces -> laurels OR oaks'

But, the solution says 'if the park doesn't have firs and spruces, then it must have both laurels and oaks.'

I don't understand why the park must have both laurels and oaks when the park doesn't have firs or spruces.

*my second question is, when you say A or B, does that mean either A or B (1 of them)? Could it also include both A and B?

Thank you in advance

[mr]

"If it is not the case that the park contains both laurels and oaks, then it contains firs and spruces."

~L           F
or   ---->   +
~O           S

~F          L
or  ---->   and
~S          O


The issue you are having is in interpreting the phrase, 'if it is not the case'. When you read this, you should realize it's not standard procedure, so slow down and go through this thought process. If it's not true that BOTH L and O are in there, then what MUST be true of L and O. After a couple seconds you should realize that one must not be there. Then complete the conditional statement and perform the contrapositive.

[mr]

As for your second question...

Strictly speaking, the phrase, if 'A or B then C', only pertains to the times when 'A or B'. When both happen, A or B is still happening.   I might need to be corrected on this, but there can be a case where there is a specific conditional statement for A AND B that overrides what I just said, but that would be a rare occurrence and would change the nature of the original conditional statement.

So yeah, it can include both.

[sg7007]

Now I understand it. Thank you very much!

[sg7007]

The third condition in this game says 'If yews are not in the park, then either laurels or oaks, but not both, are in the park.'

How do you diagram this? I did it like  '~yews -> laurels OR oaks, ~(laurels AND oaks), ~(~laurels AND ~oaks)'
This seems to make sense, but obviously, it's way too convoluted and hard to understand. This is one of the reasons why I did poorly on this game. I tried to find a similar case in LGB and LRB under the conditional reasoning chapters,but I couldn't. I hope you can tell me an easy way to diagram the statement.

[mr]

The third condition in this game says 'If yews are not in the park, then either laurels or oaks, but not both, are in the park.'

How do you diagram this? I did it like  '~yews -> laurels OR oaks, ~(laurels AND oaks), ~(~laurels AND ~oaks)'
This seems to make sense, but obviously, it's way too convoluted and hard to understand. This is one of the reasons why I did poorly on this game. I tried to find a similar case in LGB and LRB under the conditional reasoning chapters,but I couldn't. I hope you can tell me an easy way to diagram the statement.

                L
~Y ---->  or,   not(LO)  ---your graphic could be LO with a box and a line through it. or   L <--+--> O
                O


Contrapositives are:

~L
and ----> Y
~O

AND

L
and ----> Y
O


This particular game you are talking about is kind of lame in this respect. You just have to trust your instincts.

[mr]

What you have to realize is that this game is really giving you 2 conditional statements in one rule. Therefore you have 4 total conditional statements when you do the contrapositives.

[sg7007]

Ah~ Thank you so much. You guys are geniuses!

Yeah, the bibles never mention about the two conditional rules in one statement thing. In retrospect, I guess I should've started these preps two months ago. Now I have only 20 days with dozens of prep tests to go over.

[billymahogany]

I took this preptest today, and that game KILLED ME.  Are the grouping games on recent LSATs ever this hard?

[EarlCat]

I took this preptest today, and that game KILLED ME.  Are the grouping games on recent LSATs ever this hard?

They haven't been as hard.  The new trend is to put out a fairly straightforward game with at least one really weird rule (The load of the circuit is the number of switches that are on.)