Problem #PRU-5238

Problems Methods Pigeonhole principle

Problem

\(20\) birds fly into a photographer’s studio: \(8\) starlings, \(7\) wagtails and \(5\) woodpeckers. Each time the photographer presses the shutter to take a photograph, one of the birds flies away and does not come back. How many photographs can the photographer take to be sure that at the end there will be at least \(5\) birds of one species and at least \(3\) of another species remaining in the studio?