The probability of an impossible event,i.e.,$P(\phi)$,is

Let $X$ be a set containing $n$ elements. If two subsets $A$ and $B$ of $X$ are picked at random,the probability that $A$ and $B$ have the same number of elements is:

$A$ card is drawn from a well-shuffled pack of $52$ cards. The probability of getting a queen of clubs or a king of hearts is

One card is drawn from a well-shuffled deck of $52$ cards. If each outcome is equally likely,calculate the probability that the card will not be a diamond.

If a die is thrown $2$ times,what is the probability of getting $4$ at least once?

An integer $x$ is chosen at random from $1$ to $50$. The probability that $x + \frac{336}{x} \leq 50$ is