$A$ rational number is selected at random from the distinct rational numbers of the form $p/q$ formed with $p$ and $q$ belonging to the set $\{1, 2, 3, 4, 5, 6\}$. The probability that the rational number selected is a proper fraction is:

If two dice are thrown together,then the probability that the sum of the numbers appearing on them is a prime number is:

$A$ six-faced unbiased die is thrown twice and the sum of the numbers appearing on the upper face is observed to be $7$. The probability that the number $3$ has appeared at least once is:

Each of the two boxes $A$ and $B$ contain $10$ chits numbered $1$ to $10$. If one chit is drawn at random from each of $A$ and $B$,then the probability that the number on the chit drawn from $A$ is smaller than the number on the chit drawn from $B$,is

Two dice are thrown and the sum of the numbers which come up on the dice is noted. Let us consider the following events associated with this experiment:
$A:$ the sum is even.
$B:$ the sum is a multiple of $3$.
$C:$ the sum is less than $4$.
$D:$ the sum is greater than $11$.
Which pairs of these events are mutually exclusive?

$A$ coin is tossed twice. The probability of getting head both the times is