Question 113
In Teil-Land there are $n$ cities. Every two cities are connected by a one-way street that can be travelled either only by motorcycle or only by car. Show that there is a city from which every other city can be reached either by motorcycle or by car.
Remark: It is not necessary that every other city be reached by the same means of transport.
Remark: It is not necessary that every other city be reached by the same means of transport.