$A$ bag contains $3$ red and $3$ white balls. If two balls are drawn one after another,what is the probability that they are of different colors?

Out of $30$ consecutive numbers,$2$ are chosen at random. The probability that their sum is odd,is

Out of the first $5$ consecutive natural numbers,if two different numbers $x$ and $y$ are chosen at random,then the probability that $x^4 - y^4$ is divisible by $5$ is

$A$ bag contains $2$ red,$3$ green,and $2$ blue balls. Two balls are drawn at random. The probability that none of the balls drawn is blue is

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:

There are $4$ hotels in a town. If $3$ men check into the hotels in a day,then the probability that each checks into a different hotel is