Q23 - A summer day is pleasant

[aileenann]

As soon as you read the first sentence in this argument, you should realize that this is a good opportunity to whip out your set-membership or conditional logic analysis. Let's map this out in conditional statements.

The first statement can be processed pretty directly to:
If wind AND below 84 -> pleasant summer day

The second statement is a little tricky. I thought it would be easiest to break it down into two separate conditions (since either of the either or conditions can trigger the conditional statements). Probably the trickiest part here is my insertion of the "humid" condition in the if clause - I do this because this conditional statement does not apply to all summer days (as the one above does) but rather only to summer days that are already humid. It's unclear that an unhumid summer day would be oppressive over 84 if we follow the language in the conclusion.
If above 84 AND humid -> oppressive summer day
If no wind AND humid -> oppressive summer day


Now the question is asking us which of the weather reports conforms to the principles above. Let's take a look at the answer choices.

(A) does not give enough information to prove it was a pleasant day. In particular low humidity and low temperature are not enough - we also need a breeze to establish a pleasant say with the principles we know.

(B) is the whole reason we had to make sure to incorporate the humidity information above! We don't actually know anything about how a non-humid day can be oppressive - that information isn't above (and be careful - you don't want to assume that not pleasant = oppressive).

(C) gives us the wind but not temperatures BELOW 84 - right at 84 doesn't cut it given the language in the argument. Does this feel a bit lawyerly? Well it should! That shows this is a good test.

(D) does not provide what's necessary to establish an oppressive day given our criteria - since there is a breeze and the temperature stays low, neither of our conditions above gets triggered to prove an oppressive day.

(E) is the answer. This would have been harder to see if we didn't break up the second statement above into two separate conditional statements, but with our diagram above it's easy. Specifically, so long as there was no wind and it was humid, this suffices to make it an oppressive day. It doesn't matter that the temperature later dropped!

This is a tough problem. I'd recommend doing this problem more than once, as there is a lot to be learned about thinking like a lawyer *and* about conditional logic here.
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#OfficialExplanation

[geverett]

Are there any other questions you have seen with conditional logic that requires a diagram like the second sentence you have here?

[ManhattanPrepLSAT1]

Are there any other questions you have seen with conditional logic that requires a diagram like the second sentence you have here?

I just did some clean up on this post and moved it to it's proper location. Was your question about Q23 or as it was labeled previously as Q22? The second sentence on both is a conditional statement, so I wasn't sure which one you were referencing...

[geverett]

My question was indeed about #23. Pleasant, windy, humid, etc.

[ManhattanPrepLSAT1]

Not with that exact structural relationship. But the fact that they're defining a term is pretty common. So, "addition is dependance and abuse of a substance."

Addicted ---> Dependance + Abuse

But I can't think of any questions off the top of my head that have the same structure as this one.