start 4 and seven together
after 4 min 4minhourglass would e empty and 7 minhrglass would have 3 min left ,
flip 4 in hr glass after 3 min 7min hr glass would empty ,so flip it and after 1 min 4 hrmin glass woul be empty
and 7 hrmin glass have 6 min left so flip it and after and wait for 7 min hrglass to empty now nine mins have been calculated

Think about this: 44 - 17 == 9. Let us denote the four-minute hourglass by A, the seven-minute one by B. Take 2 A's and 1 B. Use the two A's consecutively and a B in parallel so that upon the completion of the B the two A's contain 1 minute each. Then launch the two A's in succession to measure the remaining 2 minutes.

Start and stop when any of the glass is empty and calculate time
4 Min>>>0 Min and 7 min>>>0 Min
0 Min>>>4 Min and 3 Min>>>4 Min ------4Min
Flip 4 min Hourglass and Continue 7Min Hourglass
3 Min<<<1 Min and 0 Min>>>7 Min ------7Min
Continue 4 Min Hourglass and Flip 7Min Hourglass
4 Min<<<0 Min and 1 Min<<<6 Min ------8Min
Flip both Now
3 Min>>>1 Min and 0 Min >>>7 Min ------9Min

Easy Math Editor

`*italics*`

or`_italics_`

italics`**bold**`

or`__bold__`

boldNote: you must add a full line of space before and after lists for them to show up correctlyparagraph 1

paragraph 2

`[example link](https://brilliant.org)`

`> This is a quote`

Remember to wrap math in \( ... \) or \[ ... \] to ensure proper formatting.`2 \times 3`

`2^{34}`

`a_{i-1}`

`\frac{2}{3}`

`\sqrt{2}`

`\sum_{i=1}^3`

`\sin \theta`

`\boxed{123}`

## Comments

Sort by:

TopNeweststart 4 and seven together after 4 min 4minhourglass would e empty and 7 minhrglass would have 3 min left , flip 4 in hr glass after 3 min 7min hr glass would empty ,so flip it and after 1 min 4 hrmin glass woul be empty and 7 hrmin glass have 6 min left so flip it and after and wait for 7 min hrglass to empty now nine mins have been calculated

Log in to reply

Think about this: 4

4 - 17 == 9. Let us denote the four-minute hourglass by A, the seven-minute one by B. Take 2 A's and 1 B. Use the two A's consecutively and a B in parallel so that upon the completion of the B the two A's contain 1 minute each. Then launch the two A's in succession to measure the remaining 2 minutes.Log in to reply

Start and stop when any of the glass is empty and calculate time 4 Min>>>0 Min and 7 min>>>0 Min 0 Min>>>4 Min and 3 Min>>>4 Min ------4Min Flip 4 min Hourglass and Continue 7Min Hourglass

3 Min<<<1 Min and 0 Min>>>7 Min ------7Min Continue 4 Min Hourglass and Flip 7Min Hourglass 4 Min<<<0 Min and 1 Min<<<6 Min ------8Min Flip both Now 3 Min>>>1 Min and 0 Min >>>7 Min ------9Min

Log in to reply