Hello, thank you for taking the time to post your question!
The key on this type of question is to set up a system of equations based on the given information. On this one we have
P = B + 13 since the Phillies won 13 more games than the Braves
P + B = 191 since combined they won 191 games
Plugging the first equation into the second and then solving for the value of B algebraically yields
B + 13 + B = 191
2B = 178
B = 89
Which means that
P = 89 + 13 = 102
So the Phillies won 102 games and the Braves won 89 games
I hope that helps get you moving in the right direction! Feel free to reach out if you have any additional questions beyond that :)