bearing in mind these two concepts that we are drilled into us
1) Money in the middle isn't yours and
2)pot odds are pot divided by price to call

Just to make this as simple as possible.

Heads up and the pot is 100. Player A donks a pot sized bet

Player b min raises it.

Player a is now being asked to call 100 into a pot of 400 so he has 4-1 or another way of saying it is he is being asked to risk 20% taking into account sunk costs and the concept that money already put in the middle isn't yours

but the problem with this is Player b has risked 200 of 400 as in 50%. How can we have a situation where one dude is risking 50% and the other is risking 20%?

it doesn't add up.

could it be that player a isn't really getting 4-1 and it just appears that way but in actuality he is only getting 1-1. But if 1-1 is true isn't that going against the idea that money in the middle isn't yours

I'd really like it if someone could clarify the answer to the question is player a getting 4-1 or 1-1 and if you could expand on it a little bit to help make it easy for me to understand

Player A is getting 4:1 to call the minraise. Period. His original donk bet isn't his money anymore.

What has changed should be his perception of player B's range and whether or not his hand is good more than 20% of the time.

No. The pot lays a price and if it's 4:1, it's 4:1. It doesn't matter how the money got into the pot, or who put it in. You only look at that one decision in isolation.

Same as when you're buying a lottery ticket. If it's $1 to win $14 million, you're getting odds of 14 million to one. You don't know or care who bought all the other tickets or if there is some sort of overlay (like a rollover from the week before). You just look at how much it costs to play the game and how much you might win.

Note: Don't do lotteries. The rake is even worse than on Stars.

By "worse" you mean less, right? You have to be specific because this is BQ and there's a lot of misinformation out there about more rake being a bad thing.

so that's just it then end of story

1 persons risk is 20% and the other persons risk is 50%.

sorry i said this wrong

player a's risk was 200 of 500 after player b completes the call so that's 40% not 50%

The difference is that player B raised to 200 into a pot that was only 200 to start with but had fold equity, hoping to win 200 by betting 200.

Player A now must bet 100 (more) into a pot that is now 400 in order to have a chance to win based on the cards (assuming that this is a river bet and player A will get to see the showdown if he calls -- no other streets to come). So, player A has to be the winner on the cards more than 20% of the time to make it a good call, while player B can win the pot either by inducing a fold or by having better cards.

thanks for that and to everyone else too.

Here is one way of looking at it, following up on KGC’s comment.

OP got 20% for Player A by taking his last bet and dividing by the total pot ; 20%=100/(400+100). If you do the same for B you get 40%=200/(200+100+100+100), but that is IF A calls. If A doesn’t call, B wins 200.

So, I suppose you can argue that the 20% difference in the required equity favoring A is to be theoretically covered by B’s fold equity. If the card equity was 50% for each player, it turns out that B’s required fold equity for EVb=EVa =100 is 1/3.

To see this, if A calls, his EV is 150 with 50% card equity. Since you should expect equal EV with 50% equity, A has to fold 1/3 of the time for an EVa of 2/3*150= 100, thus giving B an EV also equal to 100 since the EV sum has to equal the pot before the last round of bets.

I suspect there are better explanations

Thanks for the detailed reply. I followed about 80% of what you were saying but got a bit lost.

I think where I'm working it out wrong is when I'm saying b) risked 40% after the call is completed when in reality b) isn't risking 200 of 500 he is really risking 100 of 500 as is player a) also.

I can't speak for other places, but in the UK National Lottery, only 50% of the ticket price ends up in the prize pool. That's a whole lot of rake. (Pokerstars only rakes about 5% of the pot).

I was making a dumb joke about "more rake is good" a la D-Negs and Doug Polk.

1/3 of that 50% rake goes to charity as well. You're better off calling a 2/3 pot bet with only a flush draw than playing the lotto.