Calculation invloving time

Here are few example calculation in time/ duration.

Let say we want
24 hour time system
= 2 hour 35 minutes - 1 hour 50 minutes
= 45 minutes
New 20 Hie time system
= 2.153Hie - 1.528 Hie
= 0.625 Hie

Let say we want
24 hour time system
=4.40am to  8.15am
= 3 hour 35 minutes
New 20 Hie time system
= 3.889Hie am to  6.875Hie am
= 2.986 Hie

Let say we want
24 hour time system
Rate =1 hour 3.5 dollar
Time = 1 hour 43 minutes
Money = nearly 6 dollar
New 20 Hie time system
Rate =1 Hie 3.5 dollar
Time = 1.43 Hie
Money =5.005 dollar.

Let say we want calculate average speed.
24 hour time system
Duration =2 hour 20 minutes
Distance = 112km
Speed = 48km/h
New 20 Hie time system
Duration = 1.944Hie
Distance = 112km
Speed = 57.6km/Hie