First of all i would like to apologize for my bad english. I hope you understand me.
a lot of bikes are parked in front of a university. A truck unfortunately hits 10 bikes and destroy them.
of the students at the university: 20% are smoker, 40% are bikers, 25 % of the bikers are smokers.
what´s the probability that none of the 10 bikes belongs to the smokers??
It seems to me that we need more informations to solve this question?? or what?? Hope you can help