Problem #PRU-110920

Problems Methods Algebraic methods Proof by exhaustion Pigeonhole principle Pigeonhole principle (other)

Problem

Peter has some coins in his pocket. If Peter pulls \(3\) coins from his pocket, without looking, there will always be a £1 coin among them. If Peter pulls \(4\) coins from his pocket, without looking, there will always be a £2 coin among them. Peter pulls \(5\) coins from his pocket. Identify these coins.