Since i have seen this being calculated many times in a wrong way i decided to do my own version of it.
First let's settle the Timeframe
Going by my watch and my phone's timer the timeframe is 1 centisecond ( 0.01 sec)
Garou = 291 px = 1.77 m
Panel Height = 488 px
Object = 2atan(Object_Size/Panel_Height/tan(70/2))) = 44 degrees
Using this calculator we get the distance to be 2.2 m
From the third image he managed to strike Garou 16 times.
I assume that for each strike his hand should travel 1 m
Total distance = 2.2 + 16 = 18.2 m
Speed = Distance / Time = 1820 m/s (mach 5.3) Hypersonic