Let's say we have 40% equity in the hand.
Let's see how often we need to get a fold from villain to make this a good push.
Our share of the final pot if called will be $. 39,8$ * 40% = 15,92$.
We need to put 18,3$ more.
There is now 3,2$ + 4$ = 7,2$ in the pot.
Number P is 18,3$ - 15,92$ = 2,38$
Its actually like betting 2,38$ into the pot of 7,2$ with no chance of winning.
To be fair we need him to fold 1/4 to make this breakeven.
And that is with 40% equity which I think might be low.
You be the judge if fold or push is right.
Explanation of the calculation used can be found here :
http://forumserver.twoplustwo.com/showfl...&PHPSESSID=