Question

If the local time at Mumbai is 3 pm then what would be the local time at Kolkata?

Answer 1

Both the cities, and the Indian Subcontinent (Main Land and it's islands) follow the Indian Standard time (IST) as the Same standard.
So, it is 3pm in Kolkata too!!!

Answer 2

According to the Indian Standard Time for IST theory , the time difference of Mumbai and Kolkata is null. But this time is counted on an average basis.

To calculate the real difference of the local time of Mumbai and Kolkata we must apply the GMT theory.

The longitudes of Mumbai and Kolkata are,(72°54' E) & (88°24' E).

So the total longitudinal difference of these two cities are,

=(88°24' - 72°54')

= 15°30'

According to the GMT theory,4 minutes of time difference is occurred for 1° longitudinal distance.

So the actual local time difference between mumbai and kolkata is (15°30'X4) = 62 minutes

If the local time of Mumbai is 3 p.m.

The actual local time of Kolkata will be 4:02 p.m