Question

Difficulty: HardLatitude, Longitude, and Time Calculations

A radio signal transmitted live from Station X, located at longitude 78E78^\circ\text{E}, is logged at 10:40 AM10:40\text{ AM} local solar time. At the exact same instant, the signal is received at Station Y, where the local solar time is logged as 03:16 PM03:16\text{ PM} on the same day. What is the longitude of Station Y in degrees East?

Answer: 147 °E

Answer

147°E
The time difference between 10:40 AM and 03:16 PM is 4 hours and 36 minutes. Converting this time difference to degrees using 1515^\circ per hour (4×15=604 \times 15^\circ = 60^\circ) and 11^\circ per 4 minutes (36 min/4 min/degree=936 \text{ min} / 4 \text{ min/degree} = 9^\circ) gives a total longitudinal distance of 6969^\circ. Because Station Y has a later solar time than Station X, it is situated further East. Adding 6969^\circ to 78E78^\circ\text{E} yields 147E147^\circ\text{E}.

Step-by-Step Solution

1
Calculate the time difference between Station Y and Station X
4 hours and 36 minutes
Subtracting the earlier local time at Station X (10:40 AM) from the later local time at Station Y (03:16 PM) yields a duration of 4 hours and 36 minutes.
2
Convert the calculated time difference into longitudinal degrees
69 degrees
Earth rotates through 15° of longitude per hour (or 1° every 4 minutes). Thus, 4 hours corresponds to 60° and 36 minutes corresponds to 9°, giving a total of 69°.
3
Calculate the longitude of Station Y based on directional time relationship
147°E
Because local time at Station Y is later than at Station X, Station Y lies further East. Adding the angular separation of 69° to 78°E results in 147°E.

Key Concept

Longitude calculation from local time difference
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