3 months of coaching won't give you anywhere near the TD defense to stop a lifelong Judo player from your local McDojo, let alone an Olympic medalist.
That doesn't mean that Floyd can't knock Rousey out. He can... if he lands a clean, hard strike in the right place. If you think that Floyd at 5'8" and who fights at 135 pounds is knocking out Rousey with just a jab, I think you're overestimating Floyd's power. Floyd has never been a power puncher, he's an attrition/accumulated damage fighter.
Rousey is 5'7" with a walk around weight closer to 150-160. Floyd isn't exactly a towering giant. Floyd isn't powering out of a Rousey arm bar. 3 months isn't going to get him the training he needs to get back to his feet once he's on the ground either. He's not some huge guy with a 50+ pound weight advantage.
Saying 0% for either fighter is silly.
Rousey gets her paws on Floyd and he's going for a ride and it will inevitably lead to an arm bar or GnP. If Mayweather lands a really well placed overhand, hook or uppercut there's a decent chance that Rousey ends up unconscious.
Either way, it doesn't matter. Even if there was a billion dollars on the line, there's no way that Floyd takes the fight. It's never going to happen.
