An accountant and engineering convention was being held. On the train to the convention, there were both accounting and engineering majors. Each of the engineering majors had his/her own train ticket. But the accountants had only ONE ticket for all of them. The engineers started laughing and snickering. The accountants ignored the laughter. Then, one of the accountants said, "Here comes the conductor". All of the accountants piled into the bathroom. The engineers were puzzled. The conductor came aboard and collected tickets from all the engineers. He went to the bathroom, knocked on the door, and said "Ticket please". An accountant stuck their only ticket under the door. The conductor took the ticket and left. A few minutes later, the accountants emerged from the bathroom. The engineers felt really stupid.

On the way back from the convention, the group of engineering majors had ONE ticket for their group. They started snickering at the accountants, who had NO tickets amongst them. When the accountant lookout shouted "Conductor coming!", all the accountants again piled into a bathroom. All of the engineers went into another bathroom. Then, before the conductor came on board, one of the accountants left the bathroom, knocked on the other bathroom, and said "Ticket please."