#17 - Local, Must Be True

[Dave Killoran]

Complete Question Explanation
(The complete setup for this game can be found here: lsat/viewtopic.php?t=11096)


The correct answer choice is (C)

If S is performed sixth, then from the last rule O cannot be performed fifth, and we can conclude that O must be performed first, creating the following setup:

October 00_game#2_M12_L3_explanations_game#5_#17_diagram_1.png

The first rule creates either an RT or TF block, and the only remaining place for that block to fit on this diagram is in spaces four and five. Hence, the composition performed fifth must be either F or T, and answer choice (C) is correct.

[dholland]

I am struggling with this question. Can someone please explain to me why the F__+R or R__+F rule does not apply to this question. Why can the correct answer contradict one of the rules? Am I missing something?

[Adam Tyson]

There's no contradiction of that rule here, dholland - that rule is still in play and we must abide by it. The key rule for this game, as explained above, is the one that puts T in a block. One way or another, that block goes in the 4th and 5th spaces, because it cannot fit anywhere else. Let's see what those two options look like:

1. a TF block - O_PTFS_H/L. In this case, because of the rule about R and F, R must go 2nd. The only other blank space, 7th, is too close to F. Now H and L can fill the last two spaces in either order. ORPTFS(H,L)

2. an RT block - O_PRTS_H/L. Here, in order to comply with the rule about R and F, we have to put F in the 7th position, and either H or L goes 2nd. O(H/L)PRTSF(L/H)

Either way, we will end up complying with the rule you were concerned about.

Let me know if that clears it up for you, or if you need any further help with it. If the latter, tell us where you see the contradiction of that rule, and we'll see if we can show you the way around it.

Thanks for the question! Keep at it!

[KG!]

I see now why RT and TF is the case now, but any tips for looking at this rule first? I was distracted by the thinking about where R and F should go. What would you recommend is a good tip for not get fixating on particular rules.

Thank you in advance!

[Adam Tyson]

Blocks are frequently the most powerful active element in a game, KG, and when a local question like this one limits the available places for a block you should start by considering those limitations. Blocks matter because they take up multiple consecutive places instead of just one space, and they often then trigger other rules.

In this question, once you infer that O must be first, there are only a couple "active" rules left. Those are rules that still need to be satisfied in that particular scenario. The F/R rule is active, but it's a flexible rule in general and therefore not as powerful, perhaps, as the block involving T. The rule about what goes 8th is still active, but also not very influential, because once you choose one of them to go 8th the other becomes a free agent of sorts, and picking either has no other consequences on the rest of the variables. Of those three active rules, the one with the block is the only one that is 1) very restricted and 2) very consequential thanks to its impact on R and F. If you have a block to deal with, deal with it!

[KG!]

Blocks are frequently the most powerful active element in a game, KG, and when a local question like this one limits the available places for a block you should start by considering those limitations. Blocks matter because they take up multiple consecutive places instead of just one space, and they often then trigger other rules.

In this question, once you infer that O must be first, there are only a couple "active" rules left. Those are rules that still need to be satisfied in that particular scenario. The F/R rule is active, but it's a flexible rule in general and therefore not as powerful, perhaps, as the block involving T. The rule about what goes 8th is still active, but also not very influential, because once you choose one of them to go 8th the other becomes a free agent of sorts, and picking either has no other consequences on the rest of the variables. Of those three active rules, the one with the block is the only one that is 1) very restricted and 2) very consequential thanks to its impact on R and F. If you have a block to deal with, deal with it!

Thank you for this explanation!!