Two Swedes and two Norwegians are traveling...
Two Swedes and two Norwegians are traveling by train from Stockholm to Oslo. The Swedes only buys one ticket, but the Norwegians buys two. On the train, the Swedes locks themselves in the toilet. When the conductor goes by, he knocks on the door, asking for the ticket. They slip the ticket under the door, the conductor cuts it and moves on.
The Norwegians sees this, and on the way back, the Norwegians buys one ticket, but the Swedes buys none. On …