MathDB
Averages.

Source:

December 6, 2005

Problem Statement

A finite set S\mathcal{S} of distinct real numbers has the following properties: the mean of S{1}\mathcal{S}\cup\{1\} is 13 less than the mean of S\mathcal{S}, and the mean of S{2001}\mathcal{S}\cup\{2001\} is 27 more than the mean of S.\mathcal{S}. Find the mean of S.\mathcal{S}.