Problem #PRU-22001

Problems Methods Pigeonhole principle Pigeonhole principle (other) Discrete Mathematics Set theory and logic Set theory Union, intersection, and set difference
 12–14  4.0

Problem

11 scouts are working on 5 different badges. Prove that there will be two scouts \(A\) and \(B\), such that every badge that \(A\) is working towards is also being worked towards by \(B\).