The probability of happening an event $A$ is $0.5$ and that of $B$ is $0.3$. If $A$ and $B$ are mutually exclusive events,then the probability of happening neither $A$ nor $B$ is

In a set of $30$ game cards,$17$ are white and the rest are green. Out of $30$,$4$ white and $5$ green cards are marked $IMPORTANT$. If a card is chosen randomly from this set,then the probability of choosing a green card or an $IMPORTANT$ card is:

$A$ box contains $1$ red and $3$ identical white balls. Two balls are drawn at random in succession without replacement. Write the sample space for this experiment.

$A$,$B$,$C$ are three horses participating in a race. The probability of horse $A$ to win the race is twice that of horse $B$ and the probability of horse $B$ to win is twice that of horse $C$. Then the probabilities of horses $A$,$B$,and $C$ to win the race are respectively:

If $A$ and $B$ are two events such that $P(A) = \frac{1}{4}$,$P(B) = \frac{1}{2}$,and $P(A \cap B) = \frac{1}{8}$,find $P(\text{not } A \text{ and not } B)$.

Let $S$ be the sample space of the random experiment of throwing simultaneously two unbiased dice and $E_k = \{(a, b) \in S : ab = k\}$. If $p_k = P(E_k)$, then which of the following is correct?