HumorShack - Riddle #66 [Previous Riddle] [Next Riddle] Solution to Two hourglasses Turn over both hourglasses at once.  When the four-minute hourglass runs out, turn it over. When the seven-minute hourglass runs out, turn it over. When the four-minute timer runs out this time (eight minutes have  elapsed), the seven-minute hourglass has been running for one  minute. Now turn over the seven minute timer back over. When the  timer runs out, nine minutes have elapsed. [Previous Riddle] [Next Riddle]

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