If exactly five of the stations stay open, which one of the following must close?

on July 28 at 10:25PM

Confused...

I'm confused how I'd make a quick deduction out of this without trying every single answer choice before. Pleased explain deduction!

2 Replies

Irina on August 7 at 09:51PM

@Ceci,

We know from rule (4) that L & R cannot both stay open, so if exactly five stations stay open, and only one is closed, it must be L or R. We can thus eliminate answer choices (B), (C), (D).

Now we know that the rest of the stations are open, and rule (2) tells us that if N stays open, L must stay open. Thus, we can eliminate answer choice (A).

R is thus the one that must close (E)

Does this help?

Let me know if you have any further questions.

on November 2 at 07:05PM

Hi Irina, if R is out, how come M is still open?

Rule 3: R -> M
(not R -> not M)