Mutually Exclusive - when the outcome of event A can never happen at the same
time as the outcome of event B, then event A and event B are mutually exclusive
Exhaustive Events - when the probability of mutually exclusive events add up to 1, they are exhaustive events
If there is an event A, the complementary of event a
is event A not happening
To work out the probability of two
mutually exclusive events happening, add
the probabilities of all the separate events
P ( A or B) = P (A) + P (B)