all p + 1 numbers are equal
Source: 6th QEDMO problem 5 (22. - 29. 8. 2009) https://artofproblemsolving.com/community/c1512515_qedmo_200507
May 8, 2021
algebra
Problem Statement
Let be a prime number and let further rational numbers with the following property given: If one removes any of the numbers, then the remaining may be split in at least two groups , which all have the same mean value (for different distant numbers, however, these mean values may be different). Prove that all numbers are equal.