[chbot] Chock Fish contest

[Mark Atherton]

A man arrives at a Y junction in the road.

One way goes to York, the other dead ends after 10 miles.

He only has enough petrol to get to York.

Next to the junction is a house where two identical sisters live.

One sister always tells the truth, while the other sister always lies.

One sister will open the door, but he is only allowed to ask one question.

What question should he ask to find the branch in the road to York ?

-mark

PS no cheating please !