Question

What is the longitude of a place M whose local time is 11.00 am. If the local time at longitude 30°E is 2.00 pm.

Answer 1

Difference in time from 2.00 pm to 11.00 am = 3 hrs.
In 1 hr, the earth rotates through 15°
Therefore in 3 hrs the earth will rotate through 3 x 15° = 45°
Time at M is behind that at 30°E
Get the difference between the angles
= 45° – 30°= 15°
M is at longitude 15°W.