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Difficulty: MediumLatitude, Longitude, and Time Calculations

Two weather observation stations, Station A and Station B, record simultaneous solar observations. Station A is located at longitude 12∘W12^\circ\text{W} where the local solar time is 02:00 PM02:00\text{ PM}. At the exact same moment, the local solar time at Station B is 07:00 PM07:00\text{ PM}. What is the longitude of Station B in degrees East (∘E^\circ\text{E})?

Answer: 63 °E

Answer

The longitude of Station B is 63∘E63^\circ\text{E}.
The local time difference between Station A (02:00 PM02:00\text{ PM}) and Station B (07:00 PM07:00\text{ PM}) is 5 hours5\text{ hours}. Since 1 hour1\text{ hour} equals 15∘15^\circ of longitude, a 5-hour5\text{-hour} difference equals 75∘75^\circ of angular distance (5×15∘5 \times 15^\circ). Station B's local time is ahead of Station A, indicating that Station B is located further East. Starting from 12∘W12^\circ\text{W} and moving 75∘75^\circ East, 12∘12^\circ is required to reach 0∘0^\circ (the Prime Meridian), leaving 63∘63^\circ into the Eastern Hemisphere. Therefore, Station B is located at 63∘E63^\circ\text{E}.

Step-by-Step Solution

1
Calculate the time difference between Station A and Station B.
Station B (19:0019:00) is 5 hours5\text{ hours} ahead of Station A (14:0014:00).
Comparing local solar times gives the time separation between the two longitudes.
2
Convert the time difference into angular distance in degrees.
5 hours×15∘/hour=75∘5\text{ hours} \times 15^\circ/\text{hour} = 75^\circ angular distance.
The Earth rotates 360∘360^\circ in 24 hours, which corresponds to 15∘15^\circ of longitude per hour.
3
Determine the longitude of Station B from Station A across the Prime Meridian.
75∘ East−12∘W=63∘E75^\circ\text{ East} - 12^\circ\text{W} = 63^\circ\text{E}.
Station B is later in solar time, so it lies East of Station A. Moving East from 12∘W12^\circ\text{W} uses 12∘12^\circ to reach 0∘0^\circ (Prime Meridian) and the remaining 63∘63^\circ enters the Eastern Hemisphere.

Key Concept

Calculating longitude from local time difference across meridians
Estimated Time:1m 30s
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Topics

Latitude, Longitude, and Time Calculations

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