You have encountered 100 gold bars in a cave.

In the cave, a goblin shows you 3 holes in the wall. He says one hole will triple what you put in it, one hole will leave it as the same amount, and one hole will take all of your gold.

Without knowing which hole has what characteristic, how can you maximize your gold?

You can put any amount you want in the holes.

  • 3
    $\begingroup$ I guess it's a "put in all at once without checking and grab the result" situation, correct? So I can't just throw one in each, check the result and continue throwing my duplicated gold into the tripler hole all day long. $\endgroup$
    – Morfium
    Feb 6, 2018 at 11:01

1 Answer 1


Well, if I can put any amount in the holes,

I would put one bar on each and see the result and keep adding the bars inside the "good one", so I end up with 1 + (98*3) + 3 bars and so on

Or, if I can put maximum 100 bars (the total found),

I would put 33 bars inside each hole, keeping 1. I lose for sure 33 bars, but I triplicate the bars inside the good one (so I get 99 from that) and I keep 33 bars that I put in the last hole, so I get a total of 133 bars

  • $\begingroup$ Your first answer doesn't go nearly far enough. If you can put in as many times as you want, put 50 bars into any hole, if you lose it then 50 into the next, guaranteed not to lose it, either get it back or get payout. From here feed all bars into the payout hole over and over until you have all the gold in the universe. Should not take long. $\endgroup$ Feb 6, 2018 at 11:34
  • $\begingroup$ @theonetruepath yes of course, on both first and second answer you can put unlimited bars inside the correct hole, but it's not specified that you can use more than 100 bars $\endgroup$
    – Dr. Roggia
    Feb 6, 2018 at 11:38

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