#3 - According to the rules of the university's housing

[KelseyWoods]

Hi Ellen,

Your diagram is correct. We'll look into making this more clear in the explanations.

Best,
Kelsey

[adlindsey]

I got this question right, but I struggled diagramming it. I've read all the posts and the explanation, and I'm confused. I diagrammed it just like the explanation on the 1st statement says: If 4th year, then guaranteed dorm room. But all the previous posts from the past are saying it's the other way: If guaranteed dorm room, then 4th year. I ask, because, the admin explanation is the most recent post.

Also, I believe the 1st two posts (BlueBallon) on this page are from another question.

[Jonathan Evans]

Adlindsey,

I'm sorry for the difficulty. There was an error both in the diagram of the problem (Statement 1 was reversed) and in the explanation for Answer Choice A. I have corrected both.

You are correct that the sufficient condition here is "Guaranteed dorm room," which guarantees "4th year student."

GDR 4YS

The next statement is as above:

4YS & DL Pick before ~4YS

Thus we have conclusive evidence for answer choice D.

Notice the particular syntax "the only" which precedes the sufficient condition. In the absence of "the," "only" generally introduces a necessary condition. Compare the following statements:

"The only students guaranteed dorm rooms are fourth year students."

vs

"Only fourth year students are guaranteed dorm rooms."

vs

"You're only guaranteed a dorm room if you're a fourth year student."

All three are logically equivalent (In the last example "only ... if" is technically a "phrasal conjunction" in which "only" has been separated from but should be understood together with "if," i.e. "You're guaranteed a dorm room only if you're a fourth year student."). Fun syntax, dude! Thank you for spotting that mistake. Well done.