Mediocre numbers
Source: Canada Repêchage 2015/3
June 18, 2016
number theorypermutationsAverage
Problem Statement
Let be a 3-digit number with three distinct non-zero digits. We say that is mediocre if it has the property that when all six 3-digit permutations of are written down, the average is . For example, is mediocre, since it is the average of .Determine the largest mediocre number.