#21 - Local

[Jon Denning]

Question 21 is Local, with G and H visiting a city together.

Think about which city that could be, and what would happen.

First, they can't visit S together, since I is already taking one of those spots. So G and H can only go to M or T.

If G and H go to M, then H must also go to T (rule 3), as well as I (it needs a second visit, and T is all that's open). That puts F in S with I. Here's how it looks:

H F I
G I H
M S T

What about if G and H go to T? Well that's a little less certain. All we know for sure now is that I goes to M. So you're left with this:

? ? H
I I G
M S T

One of those ? must be an F, but they could both be Fs, or one could be an H or a G (as long as G is on M).

In looking at those two layouts though, what's consistent between them? What Must Be True as the question asks?

In both cases H visits T, so answer choice (D) is correct.