Please do NOT post your answer, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.
I have 2 hourglasses. One measures 7 minutes and the other measures 11 minutes. What is the quickest way to use them to time the boiling of an egg for 15 minutes?
I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED
and is available for the Kindle
and USA here
) and on the iBookstore
in the USA here
). You can try 101 of the puzzles for free here