Answer
$\frac{1}{30240}$.
Work Step by Step
We know that $\text{probability}=\frac{\text{number of favourable outcomes}}{\text{number of all outcomes}}=\frac{n(E)}{n(S)}.$
We know that $\text{number of favourable outcomes}=1$, whilst $\text{number of all outcomes}=P(10,5)=10\cdot9\cdot8\cdot7\cdot6=30240.$
Hence probability=$\frac{1}{30240}$.
