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[vespistabella]

Everyone who finished ahead of Kevin finished ahead of Lisa, and everyone who finished behind Lisa finished behind Kevin.

We can infer that . . .
(1) No one finished between Kevin and Lisa
(2) Lisa did not finish ahead of Kevin.


I chose (2) The correct answer is (1) This does not make sense to me.

A hypothetical scenario:

1, 2, 3, K, 5, 6, 7, L, 8, 9, 10 . . .

seems perfectly plausible, in which people finish between K and L. But I cannot imagine any scenario in which L finishes ahead of K.

What am I missing?

[vespistabella]

Thanks for your reply. Actually, in my hypothetical, 5 and 6 are finishing behind K not ahead of K, just like X in your example. I think we are agreeing, but maybe the way I wrote out my hypothetical was confusing.

Anyway, I just figured out that the reason that it has to be answer 1 is that L actually can finish ahead of K as long as there is no one between them. So answer 2 is wrong. L can finish before K, just not if anyone is between them.

Because if LK, then everyone who finishes behind L also does finish behind K.

I get it now. It does have to be answer #1. That allows both answers to be true.

[timmydoeslsat]

I did misinterpret your layout which you have laid out. That was my fault.

I still believe that the first answer choice listed is not something that is inferrable.

Having a situation of K - X - L does not violate any rule.

We know these 2 rules, which is conveying the contrapositive, so it is really one rule with the assumption of no ties.

L - X ---> K - X

X - K ---> X - L

So, note that we have no guidance of what is to occur if K - X.

We also have no guidance of what happens if X - L.

So we can have K - X - L without breaking a rule.

The issue with this question is that it attempts to emulate the common situation of a logic game rule structure: X is either at some time before K or after L, but not both. However this question you posted cannot give us this game inference. We can have more than the two situations of K and L coming after X, and having K and L coming before X.

The first answer is not a valid inference. Neither is the second.

[zagreus77]

The stimulus should be be changed. If and only if language could be used. What is required for 1 to follow is that those in front of of Kevin are exactly the same as those in front of Lisa, and same with the behind requirement.

Everyone who finishes in front of K and only those finish in front of Lisa -- for example would work. The same lingo could be used for the second requirement. It would have to exempt K and L too.