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'Stop the Clock' printed from http://nrich.maths.org/
A number of pupils from Mortimer School in England sent in their solutions.
Here are their comments:
Alice and Oliver:
When your partner is doing 1/2 an hour you should do a 1 hour.
Aaron and Mustafa:
Get the clock on to half past ten and then try and make him use half an hour and you use 1 hour so it goes on to 12 o'clock.
What would happen if your partner didn't use half an hour? Could you still win?
Harry and Gabe:
I pressed 1 hour when it was 11
Luke and Eve:
We think that you have to press 5 hours and 2 half hours for player 1 to win the game and 4 hours and 3 half hours for player 2 to win the game.
Dylan and Jacob:
We wrote that we did 1 hours and half an hour.
Thank you very much for these contributions. The difficulty is to find a way of winning that ALWAYS works.
Rhys from St. Michael's on the Mount in Bristol, England, sent in this email:
With this strategy if you go second you are guaranteed to win.
The aim is to get to 7.30, then 9.00, then 10.30 - after that you have won.
If player one goes to 6.30 you would go 1 hour to 7.30.
If player 1 goes to 7.00 on their opening move you would then go half an hour to 7.30.
That is a fantastic strategy, Rhys. I wonder if anyone can explain why it works?