Preston has 19 games and Horatio has 30 games.
You can set this as a system of equations, set Preston as x and Horatio as y.
Both of the amounts add up to 49, so we can get the equation:
x+y=49
Since Horatio has 11 more games, we can get the equation:
y-x=11
If we add the x to the other side, the second equation becomes:
y=x+11
We can plug in the second equation into the first and get the equation:
x+11+x=49
with a little simplification, we get x (Preston) is equal to 19. If we add 11 to it, we get Horatio's amount: 30