Three engineers and three accountants are traveling by train to a conference.

At the station, the three accountants each buy a ticket. They notice the three engineers buying only one ticket.

Accountant: “How are three people going to travel on only one ticket?”

Engineer: “Watch and you’ll see.”

On the train, the accountants take their seats. The engineers cram into a restroom and close the door.

When the conductor comes by, he knocks on the restroom door.

Conductor: “Ticket, please.”

The door opens slightly. A single arm appears holding a ticket. The conductor takes it and moves on.

The accountants are impressed and agree it’s a clever trick.

After the conference, the accountants decide to copy the engineers. They buy only one ticket for the return trip.

To their surprise, the engineers don’t buy any tickets at all.

Accountant: “How are you going to travel without a ticket?”

Engineer: “Watch and you’ll see.”

On the return trip, the accountants cram into one restroom. The engineers cram into another nearby.

After the train departs, one engineer steps out, walks to the accountants’ restroom, and knocks on the door.

Engineer: “Ticket, please.”