Question

A detergent powder company is having a contest. each pack of $1\mathrm{kg}$ contains one of the letters $B,A,M$ and $O$. In every $20$ packs; there are $4B\text{'}s,5A\text{'}s,10M\text{'}s\mathrm{and}1\mathrm{O}$. What is the probability that the pack will have $B$?

Answer 1

Given:

In every $20$ packs of detergent powder, There are

$$\begin{gathered} A=5 \\ B=4 \\ M=10 \\ O=1 \end{gathered}$$

$\begin{array}{rcl}\mathrm{Therefore},\mathrm{probability}\mathrm{that}\mathrm{the}\mathrm{pack}\mathrm{will}\mathrm{have}\mathrm{B}& =& \frac{\mathrm{Total}\mathrm{number}\mathrm{of}\mathrm{B}\text{'}\mathrm{s}}{\mathrm{Total}\mathrm{number}\mathrm{of}\mathrm{letters}}\\ & =& \frac{4}{20}\\ & & \mathrm{Dividing}\mathrm{numerator}\mathrm{and}\mathrm{denominator}\mathrm{by}4\\ & =& \frac{1}{5}\end{array}$

Hence, the probability that the pack will have $B$$=\frac{1}{5}$.