As the Memorial Day Weekend approaches, swimming pools are being filled in anticipation of the first summer holiday.
At the local Winchester pool, a certain pipe can fill it in 2 hours. Another pipe can fill it in 5 hours. A third pipe can empty the pool in 6 hours.
With all three pipes turned on exactly at the same time, and starting with an empty pool, how long will it take to fill the pool?
Solution to Problem:
The answer is 1 7/8 hours.
In 1 hour, the first pipe fills 1/2 the pool, the second
pipe fills 1/5, and the third pipe empties 1/6. That is,
in 1 hour the pool fills:
1/2 + 1/5 - 1/6 = 15/30 + 6/30 - 5/30
= 16/30 = 8/15 of the pool.
For the whole pool to fill, it would take 15/8 or 1 7/8 hours.
Correctly solved by:
| 1. Renata Sommerville | Austin, Texas |
| 2. Keith Mealy | Cincinnati, Ohio |
| 3.Walt Arrison | Philadelphia, Pennsylvania |
| 4. Eric Harding | Ashburn, Virginia |
| 5. David Powell | Winchester, Virginia |
| 6. Joe Heintz | Manchester, Tennessee |
| 7. Izzy Kushner | Closter, New Jersey |
| 8. Kirstine Wynn | Winchester, Virginia |
| 9. Richard K. Johnson | La Jolla, California |
| 10. Mr. Bennington's Math 8 Classes | High River, Alberta, Canada |
| 11. Gusti Oggenfuss | Montet, Switzerland |
| 12. Ricki Stern | Highland Park, New Jersey |
| 13. Jason Farmer | Winchester, Virginia |
| 14. Herb Shaffer | Chantilly, Virginia |
| 15. Bill Hall | Wellington, Florida |
| 16. ---------- | United Kingdom |
| 17. Erin McGinnis | Winchester, Virginia |