MathDB
Question 2

Source: Iran TST 2006

April 17, 2006
combinatorics proposedcombinatorics

Problem Statement

Suppose nn coins are available that their mass is unknown. We have a pair of balances and every time we can choose an even number of coins and put half of them on one side of the balance and put another half on the other side, therefore a comparison will be done. Our aim is determining that the mass of all coins is equal or not. Show that at least nāˆ’1n-1 comparisons are required.