LSAT Logic Games Practice Questions: The Explanation

LSAT Logic Games Practice Questions AnswersThe free LSAT Logic Game Practice Questions from last week gave some folks trouble. Here's a complete explanation of the game's setup.

Take a look at the below explanation after trying that game.


Here's a basic main diagram for the game:


LSAT Logic Games Practice Questions Answers Initial Setup













We have 7 variables (actors) being placed in a particular order, and each one is also assigned an award nomination (either gold or silver, but not both). So we have two rows of 7 spaces each.

For quick reference, the rules:

1. No two actors nominated for gold awards arrive consecutively.
2. Brad arrives before both Angelina and Lohan.
3. Depp, who is nominated for a gold award, arrives third.
4. Angelina is nominated for a gold award.
5. Brad is not nominated for a gold award only if Lohan is not nominated for a silver award.
6. Lohan does not arrive seventh.

1st rule: No two actors with gold can be consecutive, so I've placed a slash through golds touching (on the top-right).

2nd and 4th rules: B is before both A and L, and A is G. To the right of the diagram, I've written that B is before an AG vertical box and before L.

3rd rule: D is on space 3 and is G. I've placed this on the main diagram itself.

5th rule: If B is not G, then L is not S. However, every actor gets exactly one of two nominations. Therefore, we can represent "B is not G" more simply as "B is S." Additionally, we can represent "L is not S" more simply as "L is G."

Therefore, we can rewrite the rule as "If B is S, then L is G." The contrapositive (If L is not G, then B is not S) can be rewritten as "If L is S, then B is G." I've written both simplified versions of the rule to the right of the diagram.

6th rule: L is not 7th. I've simply placed an L with a slash through it above the 7th slot to indicate that L cannot go there.

Now, since A is Gold, she can't go on 2 or 4, and she can't go on 3 because D is already there. She can't go on 1 because B must go before her. Therefore, she is limited to going on 5, 6, or 7. We can create 3 different diagrams to represent these various possibilities:

LSAT Logic Games Practice Questions Answers 3 Main Possibilities for Angelina












I've also gone ahead and taken into account the fact that whomever is on either side of her, i.e. adjacent to her, cannot be gold. This is because the 1st rule told us that no actors nominated for gold awards can be consecutive.

In the top scenario, where A is on 5, L must be on 2, 4, or 6. She can't be 1st because B must go before her, and she can't go last due to the 6th rule. Therefore, no matter which space she goes on, she'll have to be S. Therefore, B must be G (due to the 5th rule), so he can only go on 1.

In the middle scenario, where A is on 6, L must go on 2, 4, or 5, all of which are S. Therefore, B must be G again, so he can only go on 1.

In the bottom scenario, however, L is not necessarily S because she can go on 5, which might be G (we don't know).

LSAT Logic Games Practice Questions Answers B on 1 in top and middle












The above is more than enough for all of you to solve the questions without much trouble. However, for those of you who would like to see how to resolve the ambiguity in that 3rd (bottom) possibility, I'm going to break it down in two different ways. The following is solely with regard to that 3rd possibility where A goes on 7. I will refer to the 4 possibilities that all fall within the 3rd possibility as 3A, 3B, 3C, and 3D.

3A: B-S on 1, which then forces L to be G and go on 5.

3B: B-G on 1 which allows pretty much anything at all to happen.

3C: B on either 2 or 4, either of which forces L to be G, so it must go on 5.

3D: B on 5, which must be G because L must go after it, on 6, which is S.

Here they are in 4 separate diagrams:

LSAT Logic Games Practice Questions Answers 3A 3B 3C 3D














Here are the 1st 2 possibilities for the game again, where A was on 5 or 6:
LSAT Logic Games Practice Questions Answers Possibilities 1 and 2






Of course, you could've stuck with the 3 original possibilities and been just fine.

That's it for the setup - the questions should be much easier now.



27 comments:

  1. Ugh, Logic Games are so frustrating. I am usually able to come up with some type of sketch and make basic deductions, but it is the deductions that come after some other event occurs that I am never able to recognize! Any tricks or strategies that I should be implementing when tackling a game?

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  2. How do you use your time efficiently in writing out all of these scenarios? Any tips help, thanks!

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  3. All this in 8.5 minutes....Wow.....

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  4. I'd like to echo Norel's sentiments. Templates here is a bit of ridiculous strategy for this question when on the clock.

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  5. there has got to be a faster way to crack this... i would not necessarily have put those four configurations for the third template (there are other ways to notate it, perhaps two broader configurations -- what happens if L is S, what happens if L is G), so how can i know that those four configurations are best for answering the questions? how can i know i even need so many templates for the questions without reading all of them first!

    is there no better way to do this? is this a realistic approximation of an actual lsat logic game?

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  6. I agree with everyone. It is really impossible to draw out all those possibilities AND read the questions AND answer them, all in less than 9 minutes. Is there something I am missing?.....

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  7. Folks, this is proof that you must just guess and be lucky when answering questions on the LSAT. What a crock of bologna that an test taker must answer this question in less than 9 minutes.

    I don't see why there must be such a time constraint when answering the LSAT questions. I mean, applicants are looking to be lawyers, not EMTs.

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    1. I second this. I feel the quality should be more important. As long as we know how to solve the question should be sufficient enough to become lawyers. But I presume in certain situations we would have to think logically on our feet. But even tho this is true, im sure it wont be logic games haha

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  8. Hi Steve, I have a question regarding this game.

    Brad is not nominated for a gold award only if Lohan is not nominated for a silver award.

    Why does this map out as B(silver) ---> L(gold) ? As opposed to L(gold) ---> B(silver).

    It seems to me that the sufficient condition is not Brad's silver nomination, but rather Linday's gold nomination. I'm unclear if perhaps I am misreading the "only if" statement. But this changes the game and the contrapositive based on how you interpret that conditional statement.

    Thanks for the help!

    Emily

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    1. In this setup, "not gold" = silver, "not silver" = gold. There are only two options, silver or gold, like two sides of a coin. Try reading the condition as "B is silver only if L is not silver." It's like saying "Jane flips a coin and gets heads if she does NOT get tails" - if Jane flips the coin and does NOT get heads, guess what she's got? Tails. Which means the opposite of Jane's first condition is also true. So for Brad:

      If L(g) --> B(s) (like you deduced)
      The opposite is also true: L(s) --> B(g)

      Does that work? (Can someone check this logic?)

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  9. i think its just a way to imagine the possibilities. a perfect score would be able to recognize the various templates and see the implications following from different placements of L in the 3rd scenario. doable but difficult.

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  10. I'm also curious about the answer to Emily's question as I too interpreted the fifth condition as L(gold) then B(silver).

    Aaron

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  11. Emily and Aaron,

    I completely understand your thoughts regarding the conditional statement of Brad and Lohan. Page 29 of the newer LG Bible addresses this type of wording. For some reason, the necessary condition follows the "only if" part of the statement. Their example is "You will get and A+ only if you study," diagrammed as A+ ---> Study. Hope this helps.

    Joshua

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  12. "only if" introduces a necessary condition, which is always AFTER the arrow, hope this helps

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  13. The time constraint issues havent been addressed yet. Steve, in your opinion, is this game realistically a 9min or less game? Or is this just more to exercise our brains?

    If this is a really a typical LSAT question, do you really suggest to work out all these templates before proceeding to the questions? Really need your opinion on this one,please!

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  14. Since this isn't a real LSAT game, don't worry about time constraints. Treat it like an exercise. And 8:45 is only an average, anyway.

    Templates aren't necessarily the best way to do this game - I just showed them for illustrative purposes. Some folks will prefer to do less work up-front and draw more diagrams over the course of the game. It's all about what you feel comfortable with.

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  15. I'd have to disagree with what some people are saying about this being unreasonable or impossible to do in 8.5 minutes.

    The way you recognize to create these templates and possibilities is by looking at the restrictions the game forces on you, and looking at the possibilities based on that. In this case, the fact that Gs cannot be together, combined with the B > A|L rules and the AG rule severely restricted As position in the game. This means that it's pretty useful to create some templates to see what would happen if A is on its different spots.

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  16. I might be the dumbest person out there, but I don't get 3 at all. If anyone has the reason why the answer is C please help me out! I've deduced it down to a,b, or. Thanks!

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    1. I know it's over a year but keep the following in mind...

      The second award must be silver, since the third award must be gold.

      Brad must have a silver award and Lohan must have a gold award.

      Lohan and Angelina are both after Brad and both must have gold awards.

      The only positions gold awards can be after Brad's 2nd award are Depp at 3rd, 5th and 7th.

      Angelina and Lohan must be in the 5th/7th spots with their gold awards but Lohan can't be 7th, so Angelina must be 7th.

      This is why the answer is C.

      I hope this helps.

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  17. Emily, you're right. What Joshua said is also correct, however: the conditional comes out to ~B(g) -> ~L(s), which is truth-functionally equivalent to L(s) -> B(g).

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  18. But this doesn't change the game, because the g/s value is binary, so ~B(g) is equivalent to B(s), etc., which gives us the two conditionals in the solution.

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  19. Alisa has it right.

    There's no need in carrying "nots" around for the medal type, since their are only two possibilities, and thus "not gold" equals "silver," and "not silver" equals "gold."

    Thus the condition is most simply stated as: B(s) -> L(g).

    The contrapositive of this is ~L(g) -> ~B(s) or, equivalently,
    L(s) -> B(g).

    Thus there are 3 possible medal combinations for B and L: [B(s) & L(g)], [B(g) & L(g)], and [B(g) & L(s)].

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    1. Note that this implies that either B or L must be gold, and possibly both are gold.

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  20. wouldn't the set up be much easier to understand if done like this, forgive operating within the constraints formatting constraints of typing this:
    1 / 2 / 3 / 4 / 5 / 6 / 7
    --------------------------------------------------------
    g / / X / D / X / A/ / A/ / A/not L/
    --------------------------------------------------------
    s / / / X / / / / not L

    X obviously represents not being able to use the block anymore. comments?

    a lot faster run run different specific examples...

    not sure if this format is going to come through...should be a simple spreadsheet with G and S on Left, 1-7 across top with individual boxes underneath.

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  21. This logic game is tough to do in 8.75 minutes for sure.. hopefully, if a question like this is on the LSAT, there are three other logic games which take on average less than 8.75 minutes to complete..

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