Question

The standard time meridian in india is 82°30'e. if the standard time at any instant is 20 hours 10 minutes, the local mean time for the place at a longitude of 20°e would be

Answer 1

time at india or 82 1/2 E longitude = 20:10=8:10pm
difference between 82 1/2E and 20E is 62 1/2
           as we are moving towards west we will reduce time
1 longitude = 4 minutes
62 1/2 longitude = 250 minutes = 4:10
thus the time on 62 1/2 longitude will be 
                                    = 8:10- 4:10
                                     =4:00 pm