#### Answer

$\dfrac{50}{5005}$

#### Work Step by Step

There are a total of $^{15}C_{6}$ possible ways to choose $6$ numbers for the winning lottery combination and this can be our denominator.
We know that $ n!=1 \cdot 2 \cdot 3 .....(n-1)n $
Thus, we have $\dfrac{50!}{^{15}C_{6}}=\dfrac{50 !}{\dfrac{15! }{(15-6)!}} $
$= \dfrac{50}{5005}$