A Problem

by bellasemplicita

Recently someone allowed me to borrow a book entitled “The Chicken From Minsk”.  It contains many different traditional Russian math and logic problems, some of which are very irritating.  If you solve the problem below post a comment on the explanation.  For those of you who don’t feel like solving it, I will post the solution next week.  Have fun!

Grandfather’s Breakfast

Grandfather is a very hard-boiled customer.  In fact, his eggs must be boiled for exactly 15 minutes, no more, no less.  One day he asks you to prepare breakfast for him, and the only timepieces in the house are two hourglasses.  The larger hourglass takes 11 minutes for all the sand to descend; the smaller, 7 minutes.  What do you do?  (Grandfather grows impatient!)

Hint:  Think carefully about the first step.  The logic is unique!