I took plan b and had unprotected sex after. can you get pregnant?

Not likely: Having sex on fertile days leads to babies, but having sex on one's non-fertile days is pretty safe, except when the woman's cycle changes unexpectedly or she calculates wrong. So, a "plan a" birth control works best. Plan b taken just before sex should work, but is not how the drug is intended to be used. If the next period doesn't come within a month as expected, one can do a pregnancy test.

Possiblity is 10%: Possiblity is 10% by estimate. If Plan B is taken within 72 hours after sex intercourse, the chance is low. But if it was taken right before that, it would n't work as expected. You have to have Plan B again within 72 hours after sex intercourse.