2

(I did not make this one up, but it's one of my favorites and I didn't see it on here!)

After a long shift at the restaurant, your fellow waiter Jeremiah proposes the following game: Start with an empty round table, and take turns placing a single round plate anywhere you want on the table. The plates cannot be stacked on top of each other but they can overhang the edge of the table. The first person who is not able to place a plate loses. Jeremiah's going to let you choose who goes first because he's a nice guy.

Do you go first or second, and what's your strategy?

Luke
  • 1,728
  • 9
  • 24
  • Should the answer depend on the ratio between the radii of the table and the plates? EDIT: Also do the plates have to balance on the table? (ie, do their centers have to be on the table) EDIT2: sniped by lorimer – Ben Frankel Sep 23 '15 at 15:07
  • 1
    Does the answer need to follow typical physics for overhanging plates (more than a certain amount extending past the edge and it falls off)? – lorimer Sep 23 '15 at 15:08
  • @JulianRosen : think you are right on it being a duplicate. I answered this by knowing the answer, but your link does refer to the same answer. – Tim Couwelier Sep 23 '15 at 15:14
  • yeah, it is a duplicate; didn't know that other one was there – lorimer Sep 23 '15 at 15:17

1 Answers1

5

The answer relies on

Symmetry

Choice:

You go first

Strategy:

You put yours first exactly in the center. After that, you mirror (well, point-symmetrical to the center) exactly what the other guy does. You'll always be certain to have a spot (given he had one last turn), so he'll run out first.

Tim Couwelier
  • 4,349
  • 21
  • 37