MathDB
2006 Combinatorics #1: Vernonia High School

Source:

July 31, 2012

Problem Statement

Vernonia High School has 85 seniors, each of whom plays on at least one of the school’s three varsity sports teams: football, baseball, and lacrosse. It so happens that 7474 are on the football team; 2626 are on the baseball team; 1717 are on both the football and lacrosse teams; 1818 are on both the baseball and football teams; and 1313 are on both the baseball and lacrosse teams. Compute the number of seniors playing all three sports, given that twice this number are members of the lacrosse team.