Total number of balls \[=\text{ }3\text{ }+\text{ }5\text{ }+\text{ }2\text{ }=\text{ }10\]
So, the total number of possible outcomes \[=\text{ }10\]
\[\left( i \right)~\] There are \[5\] black balls
So, the number of favourable outcomes \[=\text{ }5\]
Thus, P(getting a black ball) \[=~\text{ }5/10\text{ }=\text{ }1/2\]
\[\left( ii \right)\] There are \[2\]red balls
So, the number of favourable outcomes \[=\text{ }2\]
Thus, P(getting a red ball) \[=~\text{ }2/10\text{ }=\text{ }1/5\]