One out of $9$ ships is likely to sink when they are set on sail. When $6$ ships are set on sail,the probability that exactly $3$ of them will not arrive safely is

If $X$ has a binomial distribution,$B(n, p)$ with parameters $n$ and $p$ such that $P(X = 2) = P(X = 3)$,then $E(X)$,the mean of variable $X$,is

$A$ student is given $6$ questions in an examination with true or false type of answers. If he writes $4$ or more correct answers, he passes in the examination. The probability that he passes in the examination is

$A$ bag contains $4$ red and $3$ black balls. One ball is drawn and then replaced in the bag and the process is repeated. Let $X$ denote the number of times a black ball is drawn in $3$ draws. Assuming that at each draw each ball is equally likely to be selected,the probability distribution of $X$ is given by:

If the mean and variance of a binomial variate $X$ are $8$ and $4$ respectively,then $P(X < 3)$ equals to

If on an average $9$ mountain climbers out of $10$ return safely,what is the probability that with $5$ climbers out,at least $4$ will return safely?