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cc4me19
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AtlasLSAT Logic Games: 2nd Ed.?

by cc4me19 Fri Feb 19, 2010 1:30 am

I am not sure if this is the correct forum to pose this question, but here it goes anyway. I have a question about a 'Drill IT: 3D Number Line Setup Mechanics" game in the second edition AtlasLSAT Logic Games Strategy Guide. The fourth game that says: One evening, a television station broadcasts exactly six programs: M, N, O, P, R, and S. No two programs are broadcast simultaneously, ad no other programs are broadcast. Each program is either 30 minutes in lenght or 60 minutes in length. The following must be true: 1) N is 60 minutes in lenght, 2) The broadcast of S immediately precedes the broadcast of O, 3) Each 30 minute program is immediately followed by a 60 minute program, 4) P is broadcast at some time before O and 5) A 30 minute program is braodcast fourth.

I have two questions concerning the third constraint: each 30 minute program is immediately followed by a 60 minute program.

1) In the 3D setup you place a '60 minute program' in the 3rd, 5th, and 6th spots. I understand the 5th spot because it follows a 30 minute program. I don' understand why you also put it in the 3rd and 6th spot though.

2) Another question about the third constrain, you placed a special note saying that it does NOT mean that there must be a 30 minute program before every 60 minute. What confuses me about that note is, why even bother having a constrain that says that 'EACH' 30 min program is immediately followed bya 60 min program, if thats not really what it means. What also confuses me is how am I supposed to spot those types of dillemas (a constraint that doesn't really constrain) in the future?



Thanks for the help!! KT
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Re: AtlasLSAT Logic Games: 2nd Ed.?

by ManhattanPrepLSAT1 Sat Feb 20, 2010 12:48 pm

Attached is setup for anyone who would like to see what this game looks like.

AtlasLSAT_LGStrategyQuestion.pdf
(44.33 KiB) Downloaded 589 times


Very good questions!

As to your first question...

If a 30 min program is scheduled 4th, then a 60 min program must be scheduled 5th. That one you said you understood. Now, looking at the 6th spot. If we were to put a 30 min program there, we wouldn't be able to have a 60 min program following it as there is no 7th position. The 3rd constraint clearly says that each (every) 30 min program must be followed by a 60 min program. Since a 30 min program cannot be scheduled 6th, the only alternative is to assign a 60 min program 6th. For the 3rd position. If we were to assign the 3rd position to be a 30 min program, we would not have it followed by a 60 min program as the 4th position has already been assigned a 30 min program. Again, since the 3rd position cannot be assigned a 30 min program, it must be assigned a 60 min program.

As to your second question...

The rule definitely applies. Many students mistake this type of constraint to say that every 30 min program is followed by a 60 min program AND that every 60 min program is preceded by a 30 min program. However, while placing two 30 min programs back to back would violate the constraint, placing two 60 min programs back to back would NOT. This rule establishes a conditional constraint, think IF ...., THEN ....
This rule says if a 30 min program goes somewhere, then a 60 min program must follow. But does not imply what happens if a 60 min program goes somewhere.

I hope this helps!
 
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Re: AtlasLSAT Logic Games: 2nd Ed.?

by cc4me19 Sun Feb 21, 2010 5:03 pm

Thanks for the clarification!! I totally see it now.