We have a total of
9+7+3 = 19 jerseys. 7 of them are large.
The probability of picking a large jersey is:
7/19.
After you already picked up one large jersey, you're left with 6 out of 18 jerseys: 6/18
So, the probability will be:
[tex]\frac{7}{19}*\frac{6}{18}=\frac{42}{342}=\frac{7}{57}=0.122807[/tex]