Answer
$0.3$.
Work Step by Step
We know that probability of the event E is $P(E)=\frac{\text{number of favourable outcomes}}{\text{number of all outcomes}}=\frac{n(E)}{n(S)}$.
Since here we have $n(E)=3$ and $n(S)=10$, then
$P(E)=\dfrac{3}{10}=0.3$.
