Question

The Hours Up! You have two hourglasses- a 4-minute glass and a 7 minute
glass. You want to measure 9 minutes. How do you do it

Answer 1

Answer:

Flip both timers over. When the 4-min timer is empty, flip it over (the 7-min timer has 3 minutes left in the

top). When the 7-min timer is empty, flip it over (there is now 1 minute left in the top of the 4-min timer).

When the 4-min timer is empty for the second time, the 7-min timer has 1 minute worth of sand in the bottom half.

Flip it over so there is now 1 minute in the top. When the 7-min timer empties, 9 minutes have elapsed.

Answer 2

$\mathfrak{\huge{\pink{Answer:-}}}$

I have two hour glasses one of 4 min & another of 7 min.

I have to measure 9 min I'll separate the two ends of both hour glass.

I'll empty separately the 4 min glass and put the sand aside. Then I'll put the sand of 7 min hour glass into 4 min hour glass .So, it is 3 min sand. Then keep the 3 min sand aside then fill fully the seven min hourglass then again put the sand in 4 min hourglass we have another 3 mins sand. Now ,we have 6 min sand then again we repeat same process. We have another three mins sand. Now ,we have total 9 min sand I put it in hour glass and join it.

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