Q.From a bag containing 10 red, 4 blue and 6 black balls, a ball is drawn at random. Find the probability of drawing a) a red ball b) a blue or black ball c) not a black ball.

For a random experiment whose outcomes are all equally likely (no outcome is preferred over any other), the classical definition assigns to an event $A$ the probability $P(A)=n(A)/n(S)$, the fraction of all outcomes that are favourable to $A$. This single ratio - favourable outcomes over total outcomes - is the computational engine of the whole chapter: once a sample space is built and the outcomes favouring an ev …