$A$ jar contains $24$ marbles,some are green and others are blue. If a marble is drawn at random from the jar,the probability that it is green is $\frac{2}{3}$. Find the number of blue balls in the jar.

It is given that in a group of $3$ students,the probability of $2$ students not having the same birthday is $0.992$. What is the probability that the $2$ students have the same birthday?

$A$ die is thrown once. Find the probability of getting:
$(i)$ a prime number;
$(ii)$ a number lying between $2$ and $6$;
$(iii)$ an odd number.

$A$ box contains $12$ balls out of which $x$ are black. If one ball is drawn at random from the box,what is the probability that it will be a black ball?
If $6$ more black balls are put in the box,the probability of drawing a black ball is now double of what it was before. Find $x$.

Suppose we throw a die once. $(i)$ What is the probability of getting a number greater than $4$? $(ii)$ What is the probability of getting a number less than or equal to $4$?

$A$ piggy bank contains $100$ $50\, p$ coins,$50$ $Rs.\, 1$ coins,$20$ $Rs.\, 2$ coins,and $10$ $Rs.\, 5$ coins. If it is equally likely that one of the coins will fall out when the bank is turned upside down,what is the probability that the coin:
$(i)$ will be a $50\, p$ coin?
$(ii)$ will not be a $Rs.\, 5$ coin?