With a 7-minute hourglass and an 11-minute hourglass,
what is the quickest way to time the boiling of an egg
for 15 minutes?
Solution to Problem:
There are several ways to boil the egg with the two timers but the quickest is 15 minutes.
To do this, turn over both timers and start
boiling the egg.
When the 7-minute timer is finished, turn it over.
When the 11-minute timer is done, four minutes worth
of sand has drained from the 7-minute timer.
So, turn over the 7-minute timer.
When the 7-minute timer is finished, 15 minutes will
have elapsed, so take the egg off the stove.
Correctly solved by:
| 1. Kelsey Dufendach | Rockford, Michigan |
| 2. Walt Arrison | Philadelphia, Pennsylvania |
| 3. David L. Stark | Winchester, Virginia |
| 4. Keath Mealy | Cincinnati, Ohio |
| 5. Nate Troup | Arlington, Virginia |
| 6. Rick Jones | Kennett Square, Pennsylvania |
| 7. Geoff Keith | Santa Monica, California |
| 8. David Powell | Winchester, Virginia |
| 9. John Funk | Ventura, California |
| 10. Bill Hall | Wellington, Florida |
| 11. James Alarie | University of Michigan -- Flint, Michigan |
| 12. David and Judy Dixon | Bennettsville, South Carolina |