When it is 10 pm. in India, what is the local time at Helsinki located at 20° E longitude?

The longitudinal difference between Helsinki and India is: 82° 30' - 20° = 62° 30'

For 1° longitudinal difference time is 4 minutes.

So, for 62° 30' longitudinal difference the time difference is 62° 30' x 4 = 250 minutes or 4 hours 10 minutes.

As Helsinki is situated in the west of India, the local time of Helsinki will be behind the time of India.

The local time of Helsinki will be: 10 pm - 4 hours 10 minutes = 5:50 pm.