If the standard deviation of the random variable $X$ is $\sqrt{3pq}$ and the mean is $3p$,then $E(X^2) = . . . . . . .$

The probability that a bomb will hit the target is $0.8$. Out of $6$ bombs dropped, what is the probability that at least $1$ will miss the target?

$A$ dice is thrown $5$ times,then the probability that an even number will come up exactly $3$ times is

$A$ coin is tossed $100$ times. What is the probability of getting a tail an odd number of times?

$A$ 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 at least one correct answer is

An ordinary dice is rolled for a certain number of times. If the probability of getting an odd number $2$ times is equal to the probability of getting an even number $3$ times,then the probability of getting an odd number for an odd number of times is