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 Three coins (Posted on 2015-08-20)
Three coins are lying on a table: a quarter, a half dollar, and a silver dollar. You claim one coin, I’ll claim the other two, and then we’ll toss all three.
A coin that lands tails counts zero, and a coin that lands heads wins its value
(in cents, 25, 50, or 100) for its owner.
Whichever of us has the larger score wins all three coins. If all three coins land tails then we call it a draw and toss again.

Which coin should you claim to make the game fair — that is, so that each of us has an expected win of zero?

Source: Martin Gardner, “Charles Addams’ Skier and Other Problems,” in Wheels, Life and Other Mathematical Amusements, 1983.

Comments: ( Back to comment list | You must be logged in to post comments.)
 re(5): question | Comment 9 of 10 |
(In reply to re(4): question by Charlie)

Following your post, I make public the puzzle and enclose an abridged version of the solution.

I also provide exact reference of my source (had no reason to doubt its exactness).

If you have access to the original book, please Email the text with the solution, if it causes you no extra effort

I'd like  to compare  the versions re ambiguity, since both I  and perplexus solvers felt that some assumptions needed  to be added.

I have no hard feelings to the law rating someone declared,
after all it is not my puzzle.

Still, the result is really surprising.

 Posted by Ady TZIDON on 2015-08-23 05:09:23

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