Cook
Written on 12:49 am by Vja Students
You're a cook in a restaurant in a quaint country where clocks are outlawed. You have a four minute hourglass, a seven minute hourglass, and a pot of boiling water. A regular customer orders a nine-minute egg, and you know this person to be extremely picky and will not like it if you overcook or under cook the egg, even by a few seconds. What is the least amount of time it will take to prepare the egg, and how will you do it?
Ans:It should only take nine minutes to cook the egg. If you want to try to figure out how it is done in this short amount of time before seeing the answer, stop reading now. To start, flip both hourglasses over and put the egg in the water. When the four minute hourglass runs out, flip it back over immediately. When the seven minute hourglass runs out, flip that back over immediately too. One minute later, the four minute hourglass will run out again. At this point, flip the seven minute hourglass back over. The seven minute hourglass had only been running for a minute, so when it is flipped over again it will only run for a minute more before running out. When it does, exactly nine minutes will have passed, and the egg is done.
it can be cooked ibn 9 min itslef...
firt keep the seven and 4 hour glass and start simultaniously...
when the 4 hour glass emties(4 min merasure)
reverse both the hour glass simoltaneosly.. so remaining 3 will can be measerd in 7min hour glass so total (4+3=7)
now reverse the four glass.. cand 7 glass simoultneosly...
so the remainihg one min in 4 hour glass will be over.. and we are again remaining with the one min in 7 hour glass
7 + 2 = 9.. egg ready have it