$A$ jar contains $3$ red marbles,$7$ green marbles and $10$ white marbles. If a marble is drawn from the jar at random,what is the probability that this marble is white?

$1$ bag contains $4$ white and $2$ black balls. Another bag contains $3$ white and $5$ black balls. If $1$ ball is drawn from each bag,find the probability that $1$ ball is white and $1$ ball is black.

Two numbers are selected at random from $1, 2, 3, \dots, 100$ and are multiplied. The probability, correct to two decimal places, that the product thus obtained is divisible by $3$ is:

If a coin is tossed $n$ times,then the probability that the head comes up an odd number of times is:

$10$ coins are tossed. What is the probability that exactly $5$ heads appear?

$A$ bag contains $30$ balls,of which $10$ are red,$5$ are blue,and $15$ are white. Find the probability of drawing a coloured ball at random.