When success is not an impossible event,then the mean of Binomial distribution is

$A$ multiple choice examination has $5$ questions. Each question has three alternative answers of which exactly one is correct. The probability that a student will get $4$ or more correct answers just by guessing is:

If $X \sim B(n, p)$, then the value of $\frac{P(X = k)}{P(X = k - 1)}$ is

In a binomial distribution,the difference between the mean and standard deviation is $3$ and the difference between their squares is $21$,then $P(x=1) : P(x=2) =$

$A$ coin is tossed $4$ times. The probability that at least one head turns up is

Two cards are drawn successively with replacement from a well-shuffled pack of $52$ cards. The mean of the number of kings is: