Waste less time on Facebook — follow Brilliant.

Uneven hourglass

Using only a four-minute and a seven- minute hourglass, measure exactly nine minutes?

It is possible to use multiple hourglasses

Note by Beakal Tiliksew
3 years, 1 month ago

No vote yet
1 vote


Sort by:

Top Newest

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 Lalit Goel · 3 years, 1 month ago

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 Brijesh Mishra · 3 years, 1 month ago

Log in to reply


Problem Loading...

Note Loading...

Set Loading...