Question

A bag contains $5$ red, $8$ black and $7$ white balls. One ball is chosen at random. What is the probability that the chosen ball is black?

• A. $\frac{2}{3}$
• B. $\frac{2}{5}$
• C. $\frac{3}{5}$
• D. $\frac{1}{3}$

Answer 1

The correct option is B

$\frac{2}{5}$

Find the probability of getting a black.

Total number of balls $=\left\{\left(5red\right)+\left(8black\right)+\left(7white\right)\right\}=20balls$

Number of black balls $=8$

The probability of an event $A$ is given by:

$P\left(A\right)=\frac{Numberoffavourableoutcomes}{Totalnumberofoutcomes}$

Probability of getting a black ball $=\frac{Numberofblackballs}{Totalnumbersofballs}$

$$\begin{gathered} =\frac{8}{20} \\ =\frac{2}{5} \end{gathered}$$

Hence, the correct option is (b)