MathDB
fake coins are always odd

Source: Rioplatense L-1 2022 #6

December 13, 2022
combinatorics

Problem Statement

In Vila Par, all the truth coins weigh an even quantity of grams and the false coins weigh an odd quantity of grams. The eletronic device only gives the parity of the weight of a set of coins. If there are 20202020 truth coins and 22 false coins, detemine the least kk, such that, there exists a strategy that allows to identify the two false coins using the eletronic device, at most, kk times.