The probability that $A$ speaks truth is $4/5$,while the probability that $B$ speaks truth is $3/4$. The probability that $A$ and $B$ contradict each other when asked to reveal the fact is

The probability that two randomly selected subsets of the set $\{1, 2, 3, 4, 5\}$ have exactly two elements in their intersection is:

When two dice are rolled,what is the probability that at least one face shows a six?

An anti-aircraft gun takes four shots at an enemy plane moving away from it. The probabilities of hitting the plane at the first,second,third,and fourth shots are $0.4, 0.3, 0.2$,and $0.1$ respectively. The probability that the gun hits the plane is:

If one ticket is selected at random from $30$ tickets,each with a distinct number from $1$ to $30$,then the probability that the number on the selected ticket is a multiple of $3$ or $5$ is

$A$ student appears for tests $I$, $II$, and $III$. The student is successful if they pass in tests ($I$ and $II$) $OR$ ($I$ and $III$). The probabilities of the student passing in tests $I$, $II$, and $III$ are respectively $p$, $q$, and $1/2$. If the probability of the student being successful is $1/2$, then: