Hi, at page 97 it seems like two equations are put in the book out of nowhere and I can't make sense out of it.

The context is player A has a value hand 20% of the time, air 80%, the pot is 3 and we understand he bets 1. Player B has a bluff catcher.

Then the authors says x is Player A bluffing frequency, 3x is B ex-showdown equity, and then these 2 equations are in the book :

EV of B fold = 3x (sorry can't reproduce the symbols correctly)

When A bluffs more than 5%, B switches to calling all the time:

EV of B call = x – 0.2( sorry, can't reproduce the symbol for EV)

I really can't make sense out of it. If for example A bluffs 5% of the time, which is optimal, then 3x = 0,15. But how can the EV of B fold have any other value than zero ? The second equation, I also don't understand where it comes from. The result however makes sense with the first one since the result would be -0.15 for a bluffing frequency of 5%. But why do - 0.2 ? The only thing I guess is 0.2 must be A value range. But even then I can't make sense out of it, because it kind of implies B is losing on a call when he shouldn't (0.05)-(0.2).

I don't know if I should just skip the page and forget about it because I understand the idea that A must bluff 5%, value bet 20% and bet 1/3 pot, while B by the way has to call 75% of the time vs this scenario, fold all the time if A under bluff and call all the time if he over bluff. But I think it's frustrating of not understanding what the author means while everybody think this book is great.