I believe it's just 1 divided by 1.4 + 1 which turns out to be 41.6%.  So directly equity wise, yes you'd have enough.However, I don't believe you should just think in terms of equity when making these decisions.  Positional advantage is one variable that isn't taken into account.  How your opponent plays is another.An easy example is to imagine an opponent that open raises a very tight range of hands, maybe just broadways, mid pocket pairs or higher and any ace, half Kx type hands.  So fairly tight.Now imagine this opponent checks back anytime he misses the board with these hands or when he has weak pairs/draws.  He also gives up with his high cards/weak pairs if you make 1-2 street bets.Now against this opponent (you'd call him very weak tight and there are some players like this that won't adapt that quickly at the lower stakes), you could justify calling just about any two cards preflop, just because you can constantly steal the pot from him everytime he doesn't make 2nd pair or better (quite often).  Apply that example to situations where you're facing an opponent you feel is a good aggressive player, or just an aggro you haven't quite figured out yet, and you can see how limited you may be postflop with hands, even if they match up equity wise with the odds you're being offered.