11:00 a.m.
Explanation
The Earth rotates on its axis from West to East, completing a full circle of 360° in approximately 24 hours. This rate of rotation implies that the Earth covers 15° of longitude in one hour (360° ÷ 24 hours = 15°). Consequently, time varies by 4 minutes for every 1° of longitude.Calculation:
- Reference Point: Greenwich (Prime Meridian) is at 0° longitude. The time is given as 12:00 noon.
- Target Location: The place is located at 15° West longitude.
- Longitudinal Difference: The difference between 0° and 15° W is 15°.
- Time Difference: Since 15° corresponds to 1 hour of time difference, the gap is exactly 1 hour.
- Directional Adjustment: Places to the West of Greenwich are behind in time (earlier) relative to Greenwich Mean Time (GMT). Therefore, time must be subtracted.
- Final Time: 12:00 noon - 1 hour = 11:00 a.m.
Key Takeaway: Local time decreases by one hour for every 15° shift westward from the Prime Meridian and increases by one hour for every 15° shift eastward.