by interestedintacos Wed Jan 26, 2011 9:58 am
What's missing from that diagram:
We also know that since we are dividing 5 students into 2 cities and at least two must go in each city, there's only one possible unfixed allocation/number distribution: 2-3.
It's worth it to create a diagram with 3 slots and 2 slots vertically placed (leaving out the labels for which city will be which). You can then plug in S/P (since we know they can't go together) in the first slot in each column. You can also plug in the HR block into the column with 3 slots, since it's too big to go into the other column. That only leaves one slot open, and it must go to L. You can then use this diagram to quickly conquer the game (even redrawing it as a mini diagram next to each question and filling in which city will be which).
S/P
H S/P
R L
The important thing was to rise above the uncertainty about which city will have 3 and which will have 2 visitors (and which city won't be visited at all).