The chance of throwing a total of $7$ or $12$ with $2$ dice is:

In the following experiment,specify the appropriate sample space: $A$ person is noting down the number of accidents along a busy highway during a year.

If $A$,$B$,and $C$ are mutually exclusive and exhaustive events of a sample space $S$ such that $P(B) = \frac{3}{2} P(A)$ and $P(C) = \frac{1}{2} P(B)$,then $P(A) = $

Two numbers $a$ and $b$ are chosen at random from the set of first $30$ natural numbers. Then the probability that $a^2 - b^2$ is divisible by $3$ is (in $/87$)

$A$ box contains $10$ good articles and $6$ defective articles. One article is chosen at random. What is the probability that it is either good or defective?

$A$ bag contains $9$ discs of which $4$ are red,$3$ are blue and $2$ are yellow. The discs are similar in shape and size. $A$ disc is drawn at random from the bag. Calculate the probability that it will be not blue.