If P(E) and P(E’) are the probabilities of two complementary events, then which of the following is always true?
The correct option is B P(E)+P(E′)=1
In a random experiment, the probabilities of all possible events must total to 1,
which means some or the other outcome must occur on every trial.
Now, in a complementary event there are only two possible outcomes.
P(E) + P(E’) = 1.
Or, the correct option is B.