Condom broke, all sperm went inside her immediately got plan b what are the chances of pregnancy?

Possible: Anytime you have unprotected sex, there is a possibility of pregnancy. People are not as predictable as we might like and both sperm and egg have been known to be viable longer than expected. Plan B may be about 50% effective. Always use condoms for std protection and another effective birth control method when you have sex, if being a parent is not something you want at this time!