Let’s take an example: here, Card 1 is supposed to hit Card 2:

Card 1 Speed = X 

Card 2 Speed = Y

Default chance of miss = 5%

If not missed, and Y<=X then hit

But, if Y>=X,

Then, if Y-X >=9 then chance of miss = 95%

else chance of miss = (Y-X)*10%

Let’s put values here and see what’s happening:

Arjun’s speed (X) = 3

Jayadrath’s speed (Y) = 4

Case 1: Arjun attacks Jayadrath

Since X is lower than Y

Default chance of miss = 5%

But if not missed, chance of miss = (4-3)x10% = 10%

Case 2: Jayadrath attacks Arjun 

Since Y is higher than X

Default chance of miss = 5%

But if not missed, since Y>=X it’ll be a HIT