Four men, Mr North, Mr South, Mr East and Mr West played bridge one evening. Before playing each rubber the men cut for partners and seats at the table, the seats being in the bridge convention labelled north, east, south and west, clockwise round the table.
They played nine rubbers and discovered that no one had sat in the seat corresponding to his name in any of the nine rubbers.
The seating arrangements had been different in each of the nine rubbers.
Mr West had won all nine rubbers.
How many rubbers did Mr North win?
In the nine rubbers the men must have been seated as follows for the seats north, east, south and west:
West, North, East, South
West, South, North, East
West, South, East, North
East, North, West, South
East, South, West, North
East, West, North, South
South, West, North, East
South, West, East, North,
South, North, West, East
In the second and eighth of these Mr North partnered Mr West, and so won two rubbers.
These are the only nine ways the players could be arranged, but the rubbers need not have been played in this order.