Puzzle 22: Making Eggs
It is breakfast time and you want to cook a perfect hard boiled egg. You know that the perfect egg takes 9 minutes. So, to make the perfect egg, you need to make sure the egg is in boiling water for exactly 9 minutes. The water is now boiling, but you only have a 4 minutes and a 7 minutes hourglass timer.
How do you use these two hourglass timers to measure the cooking time is so that you have exactly a 9 minutes egg?
NOTE: You have to wait for all the sand to go down from one side as you cannot just eyeball what is "half way." Also, you must use these two timers.
Extension: Can you make eggs with 1 to 20 minutes cooking time?
How do you use these two hourglass timers to measure the cooking time is so that you have exactly a 9 minutes egg?
NOTE: You have to wait for all the sand to go down from one side as you cannot just eyeball what is "half way." Also, you must use these two timers.
Extension: Can you make eggs with 1 to 20 minutes cooking time?