Indian Standard Time is based on 82 1/2° E longitude. So if the time in India is 12 noon, so it will be 6.30 A.M. in England or GMT. The time difference between 0° and 82 1/2° E will be 82.5 × 4 – 330 minutes or 330 ÷ 60 = 5 1/2 hours. So there is difference of 5 1/2 hours between India and England, as England **** in the west, so the time will be 5 1/2 hours less than India.
An Example:
A cricket match was to be held at Birmingham at 9 a.m. local time. The position of Birmingham is 5° W. Calculate the time the viewers have to tune their television in Sydney 151°E. Answer: The local time at Birmingham is 9 am. The location of Birmingham is 5° W of Prime Meridian. The GMT would be 9:20 a.m. [9.00hrs + (5° × 4min) = 9.00hrs + 20 min = 9.20 a.m. Sydney is located at 151 °E of Prime Meridian At any point of time Sydney would be 151 × 4 = 604 min = 10 hrs 4 min ahead of GMT ( Sydney is to the East of the Prime Meridian so local time would be ahead of GMT) When it is 9:20 a.m. GMT the local time at Sydney would be (9:20 + 10:04) 19:24 hrs or 7:24 p.m. in order to watch the Brimingham match at Sydney the viewers would have to tune their televisions at 7:24 p.m. local time.
