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metallicats

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#1211 Sand-glass I.

Posted by metallicats on 27 June 2007 - 06:01 AM

You can correctly time 9 minutes by repeatedly flipping over the two glasses in this order:
each 1 stands for a minute and ** stands for flip

1 1 1 1*1 1 1 1*1 1 1 1*1 1 1 1*1 1 1 1
*********1 1 1 1 1 1 1*1 1 1 1 1 1 1

once the one seven minute glass is done, there is only one minute left in the four minute glass. two more flips of the four minute glass will get you nine minutes. To make it easier, start the four minute glass and when it's half full flip the seven minute glass.
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