Hard Riddle... need help!?!

man this is hard my had hurts i would broke both of them

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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.

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7 mins 4 mins
turn them both over and allow 4 to run out
3 mins 0mins (i.e. 4 mins)
turn both again and allow 3 to run out
0 mins 1 min
turn over again and allow 1 to run out
6 mins 0 mins
turn again allow 4 to run out
2 mins 0 mins

let the 2 minutes run then turn it over for the 7 minutes. tada

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you can use a clock, but then if you use a clock whats the point in timing lol

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I dont get it .. the people that says turn both over the first time you turn the 7 and the 4 one that would already be 11 minutes so they doesnt work... oh well

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So you start them both at the same time, when the 4min timer runs out you have 3mins left in the 7mins, you flip over the 4min timer and when the 3min timer runs out you have 1 min left in the 4min timer, you flip over the 7min timer and when the 1min runs out you have 6mins left you then flip over the 4min timer and when it runs out you two min left in the 7min timer, you then flip the 4min timer and when the two mins run out of the timer you then have two mins left in the 4min timer so you stop then, so when you need 9mins you start the 2mins remaining and when it runs out you start the seven min timer and there you go.

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wow... the people that got it right are really smart..

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