Measuring 9 minutes from 2-hour glasses Puzzle

July 9, 2022

Measuring 9 minutes from 2-hour glasses Puzzle

Using only a Four-minute hourglass and a seven-minute hourglass, How will you measure exactly nine minutes?
Restriction:- The process should not take longer than nine minutes.

Measuring 9 minutes from 2-hour glasses Puzzle

Solution

We measure 7 Minute from One Hourglass.
We reverse it at 7th minute
And, 4+4=8 Minutes from Second Hourglass          –   8 Minutes
8 (from 1) – 7 (From 2)  =                        1 Minute      –   1 Minutes
TOTAL = 9 MINUTES

Detailed Solution

Step-Wise Solution for Measuring 9 minutes Puzzle

0 Minutes – Start both hourglass at the same time.

Using only a Four-minute hourglass and a seven-minute hourglass

4 Minutes – The four minute glass runs out. Flip the four minute glass.

Step-Wise Solution for Measuring 9 minutes Puzzle

7 Minutes – The seven minute glass runs out. Flip the seven minute glass.

Using only a Four-minute hourglass and a seven-minute hourglass

8 Minutes – The four-minute glass runs out; the seven-minute glass has been running for one minute. Flip the seven-minute glass.

Measuring 9 minutes from 2-hour glasses Puzzle

0 Minutes – Start both hourglass at the same time.

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Measuring 9 minutes from 2-hour glasses Puzzle