Are you trying to find the probability of B given all n events, that is, Pr[B|A1, A2, ..., An]? In that case, none of the calculations Pr[B|A1], Pr[B|A2], ..., Pr[B|An] are useful, necessarily. In fact, even if each Ai individually makes B more likely, together they may make B less likely.
(For example, suppose we are rolling a fair 6-sided die, and take A1 = "We get 1 or 3", A2 = "We get 2 or 3", and B = "We get 1 or 2". Then Pr[B] = 1/3 before we condition, since 2 out of 6 outcomes satisfy B. If we learn either A1 or A2, then Pr[B|A1] = Pr[B|A2] = 1/2, since 1 out of the remaining 2 outcomes satisfies B. However, if we learn both A1 and A2, then Pr[B|A1,A2] = 0, because then we know that the outcome must be 3.)
If this is not what you mean, please elaborate.
Thank you. I want to pick the exact A that would point me to B. But I apologize, I should have labeled them A (and -A), C (and -C), D (and -D)..., because they are actually different things that happen simultaneously with B. There might be (should be, even) interdependence between them (at least most of them), so I won't use it as a very reliable indicator. Just a way to quickly estimate what I expect to see.
I think it's past time for another Stupid Questions thread, so here we go.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Please respect people trying to fix any ignorance they might have, rather than mocking that ignorance.