I need to know the working procedure of this sum , these 2 sums are from the ets mathsreview pdf file.
1) Given P(AUB)=0.60 and P(A)=0.20
(a) Find P(B) given that events A and B are mutually exclusive.
(b) Find P(B) given that events A and B are independent.
2). Lin and Mark each attempt independently to decode a message. If the
probability that Lin will decode the message is 0.80, and the probability
that Mark will decode the message is 0.70, find the probability that
(a) both will decode the message
(b) at least one of them will decode the message
© neither of them will decode the message
Can u help with the working procedure of these 2 sums,
the answers are 1)(a)0.40 (b)0.50
2)(a)0.56 (b)0.94 ©0.06