If three integers are selected at random from the first $20$ integers,what is the probability that their product is even?

Two cards are drawn at random from a standard pack of $52$ cards. The probability that the draw consists of exactly one face card and exactly one ace card is

If three letters can be posted to any one of the $5$ different addresses,then the probability that the three letters are posted to exactly two addresses is:

$A$ dice is rolled three times. The probability of getting a larger number than the previous number each time is:

If each of the coefficients $a, b, c$ in the equation $ax^2 + bx + c = 0$ is determined by throwing a die,then the probability that the equation will have equal roots is:

Five numbers $x_{1}, x_{2}, x_{3}, x_{4}, x_{5}$ are randomly selected from the numbers $1, 2, 3, \ldots, 18$ and are arranged in increasing order $(x_{1} < x_{2} < x_{3} < x_{4} < x_{5})$. The probability that $x_{2} = 7$ and $x_{4} = 11$ is