$A$ bag contains $6$ white,$7$ red,and $5$ black balls. If $3$ balls are drawn from the bag at random,then the probability that all of them are white is

Three numbers are selected randomly between $1$ to $20$. Then,the probability that they are consecutive numbers will be

$A$ five-digit number is formed using the digits $1, 2, 3, 4, 5$ without repetition. What is the probability that the number is divisible by $4$?

$A$ committee of two persons is selected from two men and two women. What is the probability that the committee will have exactly one man?

$A$ bag contains $5$ white,$7$ black,and $4$ red balls. If three balls are drawn at random from the bag,what is the probability that all three balls are white?

Five persons enter a lift cabin in the cellar of a $7$-floor building (excluding the cellar). If each of them independently and with equal probability can leave the cabin at any floor out of the $7$ floors (beginning with the first), then the probability that all $5$ persons leave the cabin at different floors is: