What is the probability that a number formed using all the digits $1, 2, 3, 4, 5$ is divisible by $4$?

$A$ bag contains $21$ toys numbered $1$ to $21$. $A$ toy is drawn and then another toy is drawn without replacement. The probability that both toys will show even numbers is

$A$ bag contains $5$ blue and an unknown number $x$ of red balls. Two balls are drawn at random. If the probability of both of them being blue is $\frac{5}{14}$,then the value of $x$ is equal to

$A$ basket contains $3$ mangoes and $3$ apples. If two fruits are selected at random,what is the probability of getting one mango and one apple?

$A$ 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?

$A$ 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?