Scores in a Talent Show
Source: 2011 IrMO Paper 1 Problem 5
February 8, 2018
combinatorics
Problem Statement
In the mathematical talent show called “The -factor” contestants are scored by a a panel of judges. Each judge awards a score of (‘fail’), (‘pass’), or (‘pass with distinction’). Three of the contestants were Ann, Barbara and David. Ann was awarded the same score as Barbara by exactly of the judges. David declares that he obtained different scores to Ann from at least of the judges, and also that he obtained different scores to Barbara from at least judges.In how many ways could scores have been allocated to David, assuming he is telling the truth?