16.
The teams in a netball tournament have come from five different cities: Birmingham, Carlisle, Edinburgh, Oxford, and Newcastle. Each team wore dresses and trainers of different colours out of the following: white, black, green, purple, and red. No two teams wore matching dresses and trainers of the same colour.
The Oxford team wore red dresses. Their trainers were neither white nor purple.
The Edinburgh team wore purple dresses, and their trainers were not red.
The Carlisle team wore green trainers. Their dresses were the same colour as the Oxford team's trainers.
The Birmingham team did not wear green dresses or purple trainers.
