The average interval between eruptions of "Old Faithful" is 94 minutes.
An eruption lasts 1.5 to 5 minutes.
Castle Geyser at Yellowstone National Park erupts every 12 hours while Cliff
Geyser erupts every 35 minutes.
If all three geysers erupt at the same time, how many days would elapse
until the next time that they all erupt at the same time?
Solution to the Problem:
The answer is 236,880 minutes or 3,948 hours which equals 164.5 days.
You need to find the least common multiple of the three periods:
94 minutes, 35 minutes, and 720 minutes.
Factoring each of these three numbers,
94 = 2 x 47,
35 = 5 x 7, and
720 = 2 x 2 x 2 x 2 x 3 x 3 x 5.
Hence, the LCM would equal
2 x 2 x 2 x 2 x 3 x 3 x 5 x 7 x 47 or 236,880 minutes.
Dividing by 60 yields 3,948 hours, and dividing by 24 gives
the answer of 164.5 days.
Correctly solved by:
| 1. Akash Patel | Columbus, Georgia |
| 2. Walt Arrison | Philadelphia, Pennsylvania |
| 3. Bill Funk | San Antonio, Texas |
| 4. Richard Johnson | La Jolla, California |
| 5. Rick Jones | Kennett Square, Pennsylvania |
| 6. John Funk | Ventura, California |
| 7. James Alarie | University of Michigan -- Flint Flint, Michigan |
| 8. Jim Kennedy | Limerick, Ireland |
| 9. Chris McCormick | Winchester, Virginia |
| 10. Nate Wilson | Winchester, Virginia |
| 11. Jeffrey Gaither | Winchester, Virginia |
| 12. David & Judy Dixon | Bennettsville, South Carolina |
| 13. Ashley Neumann | Winchester, Virginia |
| 14. Le My An | Ho Chi Minh City, Viet Nam |
| 15. Keith Mealy | Cincinnati, Ohio |
| 16. Michael Jacobs | Winchester, Virginia |
| 17. Laura LaRusso | Winchester, Virginia |
| 18. Ashleigh Rogers | Winchester, Virginia |
| 19. Franklin Harcourt | Columbus, Georgia |
| 20. Misty Carlisle | Winchester, Virginia |
| 21. Frank Sitarski | Plainville, Massachusetts |
| 22. Evelyne Stalzer | Montville, New Jersey |