Question 109
In one country there are finally many cities and finally many roads. Each road connects two different cities and two cities are connected by at most one road. All roads can be driven in both directions and the road network is set up in such a way that you can reach every city from any other city (possibly via detours). There is also an even number of streets for each city that lead away from this city. The government now decides to convert all roads into one-way streets. This should be done in such a way that for each city the number of roads leading out is the same as the number of roads leading into it.
a) Show that this is always possible.
b) shows that you can still reach every city from everyone else, no matter how the government implements its plan.
a) Show that this is always possible.
b) shows that you can still reach every city from everyone else, no matter how the government implements its plan.