An unbiased die with faces marked $1, 2, 3, 4, 5$ and $6$ is rolled four times. Out of the four face values obtained,the probability that the minimum face value is not less than $2$ and the maximum face value is not greater than $5$ is: (in $/81$)

Two dice are rolled one after the other. The probability that the number on the first die is smaller than the number on the second die is:

The probability that a person $A$ completes a work in a given time is $\frac{2}{3}$ and the probability that another person $B$ completes the same work in the same time is $\frac{3}{4}$. If both $A$ and $B$ start doing this work at the same time,then the probability that the work is completed in the given time is

Let $S$ be a set of $5$ elements and $P(S)$ denote the power set of $S$. Let $E$ be an event of choosing an ordered pair $(A, B)$ from the set $P(S) \times P(S)$ such that $A \cap B = \varnothing$. If the probability of the event $E$ is $\frac{3^p}{2^q}$, where $p, q \in N$, then $p+q$ is equal to

If $A$ and $B$ are two events of a random experiment,$P(A) = 0.25$,$P(B) = 0.5$ and $P(A \cap B) = 0.15$,then $P(A \cap \bar{B}) = $

The probability of a sure event is