$A$ bag contains $5$ white,$7$ red,and $8$ black balls. If four balls are drawn one by one without replacement,what is the probability that all are white?

Two tickets are drawn at random from tickets numbered $1$ to $20$. The probability that the numbers on both tickets are prime numbers is ..........

In a lottery,$50$ tickets are sold,in which $14$ are prize-winning tickets. If a man buys $2$ tickets,what is the probability that he wins at least one prize?

Two cards are drawn at random from a pack of $52$ cards. The probability of these two being Aces is

$A$ bag contains $9$ identical black balls numbered $1$ to $9$ and $4$ identical white balls numbered $1$ to $4$. If $3$ balls are drawn at a time randomly from that bag,then the probability of getting at least one white ball is

$A$ box contains $8$ red and $x$ number of green balls. $3$ balls are drawn at random. If the probability that all $3$ balls are red is $\frac{7}{15}$,then the number of green balls $x$ is: