MathDB
Fair coin-tossing

Source: Kürschák 1990, problem 3

July 20, 2014
probabilitycombinatorics unsolvedcombinatorics

Problem Statement

We would like to give a present to one of 100100 children. We do this by throwing a biased coin kk times, after predetermining who wins in each possible outcome of this lottery.
Prove that we can choose the probability pp of throwing heads, and the value of kk such that, by distributing the 2k2^k different outcomes between the children in the right way, we can guarantee that each child has the same probability of winning.