A bag contains $\displaystyle 25$ balls. Some of them are yellow and others are green. One ball is drawn at random. If probability of getting a green ball is $\displaystyle 3$/$\displaystyle 5$, then find the number of yellow balls.

\(\displaystyle \mathrm{P}(\) getting a yellow ball \(\displaystyle )=1-\mathrm{P}(\) getting a green ball \(\displaystyle )\) \(\displaystyle \Rightarrow \frac{\text { Number of yellow balls }}{25}=1-\frac{3}{5}=\frac{2}{5}\) ⇒ Number of yellow balls \(\displaystyle =25 \times \frac{2}{5}=10\)