When there is noon at G.M.T. meridian, people at another place on the Earth are taking their 6 o’clock morning tea. The longitude of the place is

1. 17° 30’ E
2. 7° 30’ W
3. 172° 30’ E
4. 90° W

Explanation

Option (d) is correct

• When it is 12:00 noon at the Greenwich meridian (GMT), a place that is 6 hours behind will show 6:00 AM. Since the Earth rotates 360° in 24 hours, it covers 15° of longitude per hour (or 1° in 4 minutes). Thus, a 1-hour time difference equals 15° of longitude. A 6-hour difference corresponds to 6 × 15° = 90°. Because the local time is earlier than GMT, the location lies to the west of Greenwich — at 90° W longitude.

Answer: (d) 90° W