Question

suppose i live on 40 degree east and your are on 20 degree west find out the time differences between tow points ?

Answer 1

For each longitude there is a time gap of 4 mins.
So, the total diff, in longitude= 40+20=60°

So the time diff. = 60X4mins=240 mins or 4 hours

Answer 2

the difference between the two regions = 40 + 20 = 60°

 360° difference  means  24 hours - a day.
  60°   means  =  60 /360  * 24  =  4 hours.

Each degree means a time difference of  24 hours / 360°
         = 24 * 60 min / 360°  =  4 minutes.
We could also use this to calculate the time difference between two zones.