You clearly understand that the first part is essentially saying what is the probability of event A and event B occurring, so this is a great start.
Next on your agenda though, should be understanding what the following questions are really asking in 'wordy' terms.
(b) = What is the probability of event B
not happening (because of the '),
given that event A has happened (because of the | prior to A).
(c) = What is the probability of event A
not happening,
or event B happening
or event A not happening, and event B not happening.
First look at B... Now you know what the question is really asking, you now need to know your formulae:
The probability of A given B.. ( P(A|B) ) = P(A∩B)/(B)
So for (b)... applying this formula, the probability is (B'∩A)/(A)
If you cannot answer the question from here..
I suggest reading the notes on probability in post #4, here:
http://www.thestudentroom.co.uk/showthread.php?t=1619124What you will see is that to go any further, as TenOfThem suggested, you must familiarise yourself with Venn Diagrams