$A$ card is drawn at random from a well-shuffled deck of $52$ cards. What is the probability that the card is red or a queen?

If the probability of an event occurring is $3:8$,what is the probability of the event not occurring?

There are $100$ lottery tickets numbered from $1$ to $100$. If a ticket is drawn at random,find the probability that the number on it is a multiple of $3$ or $5$.

Let $A$ and $B$ be two events such that $P(A) = 0.3$ and $P(A \cup B) = 0.8$. If $A$ and $B$ are independent events,then $P(B) = $

$A$ person $P$ speaks the truth in $75\%$ of cases and another person $R$ in $80\%$ of cases. What is the probability that they are likely to contradict each other in narrating the same event?

Given $P(A) = \frac{3}{5}$ and $P(B) = \frac{1}{5}$. Find $P(A \text{ or } B)$,if $A$ and $B$ are mutually exclusive events.