Question

At a Town A (30 degree West),the time is 1 p.m.,and at that moment the time is 8 p.m.at town B. Work out the longitude of town B.

Answer 1

Computing time for any longitude is very simple and easy. Longitude refers to the imaginary lines that bisect the globe through the North and South Poles. Line goes over Greenwich is considered as 0 degree. other lines are imagined references to that.

Lines from both sides meets at 180 degree on the other side of globe, which can be roughly refereed to International Date line (even though its not a straight line).

ow if we imagine a longitude line in every 1 degree, we have 179 towards right side from Greenwich line and 179 towards west, and Greenwich line and International date line, so a total of 360 imaginary lines will be drawn. This 360 lines will have a total time difference of 360 degree (a full circle of Globe).

To simplify 360 degree has a time difference of 24*60 minutes. So 1 degree will have a time difference of 24*60/360 = 4 minutes.

Now if we move towards east from Greenwich, time difference will be added and vice-versa for west.

To answer the questions

69 Deg means 69*4=276 min, East means time will be added. 12 Noon at Greenwich means 69 deg east will be 12 + 4 hr 36 min (276 min) = 4:36 pm.


30 deg means 30*4=120 min, West means time will be subtracted. 12 noon in Greenwich means 30 deg west will be 12 - 2 hr (12 min) = 10 am.12 deg means 12*4=48 min, East means time will be added. 12 noon in Greenwich means 12 deg east will be 12 + 48 min = 12:48 pm.