probability and random variables

a. in binary communication channel, the probability that a transmitted '0' is recived as a '0' is 0.85 and the probability that a transmitted '1' is recived as '1' is 0.8. If the probability that a '0' is transmitted is 0.4, then find the probability that '1' was transmitted given that a '0' was recived? b. EM and 3 two independent events such that P(A) = 0.5 and P(A U E) = 0.6, then find P(A n B)