if events a and b are general events, neither mutually exclusive nor independent, then p(a and b) = ?
for general events,
p(a and b) =p(a) x p(b|a)
or
p(a and b) =p(b) x p(a|b)
where p(a|b), the conditional probability of a given b, means that we will pretend that condition b is true and, given that condition, figure out the probability of a.