Post Series: Fun with Maths

Sasha, with four other children, was contesting for an interesting game. All the four children had cleared all the other levels and the last round was to decide the first three winners. Sasha’s eyes were set on the first prize that was ‘a beautiful pink princess gown’ that she had seen in most of the fairy tale movies.

The turn was given one by one, and there was a lifeline of ‘phone a friend’.

The last question for Sasha that came up was as follows:

If a four-minute hourglass and a seven-minute hourglass is given to you, how will you measure the exact time of nine minutes?

There is one condition too. It is that the process should not take more than 9 minutes.

Fun with Maths - The Pink Princess Gown

Challenge: Sasha thinks for a while and then chooses to use her lifeline of ‘phone a friend’. If YOU are the friend Sasha calls, then help her in answering the question so that she wins the beautiful gown.

Click here to view the ANSWER


  1. Start both hourglass at the same time.
  2. The four minute hourglass will run out. Flip it over. (Time taken: 4 minutes)
  3. The seven-minute hour glass will run out. Flip it over. The four minute hour glass is still running.
  4. The four-minute hour glass will run out. Flip it over once again. (Time taken: 8 minutes)
  5. Simultaneously, flip the seven minute hourglass also. It had run only for one minute. So now it will run for that one minute. (Hence, total time taken: 9 minutes)

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Fun with Maths – The pink princess gown
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