Could blue belt in bjj beat a black belt in another style?

Depends on who the Blue Belt is from, and what art the black belt was trained in...if it's a blue belt from a Gracie school, or some other great school, then I would say it's more likely, but again, it really depends on what the black belt was in. Also, in martial arts, anything can happen...I mean, Matt Serra beat GSP back in the day, and we all know that should've NEVER happened, haha