On the BCCIS East field trip to the Egyptian Museum, your class stayed too long in the tomb exhibit and the doors sealed behind you. Fifteen chambers stand between you and the exit, and the torches last only 60 minutes. Each lock opens only with the right number. Hints are free. Stuck after three tries? You can reveal the solution, but it burns 5 minutes of torchlight.
Reads each chamber out loud to the team.
Works out the maths, step by step.
Checks the answer makes sense. Nobody presses "Try the lock" until the checker agrees.
Writes the team's working on paper for every chamber.
Swap roles after Chambers 3, 6, 9 and 12. Everyone takes a turn at every role.