Together preston and horatio have 49 video game horatio has 11 more games than preston how many games does each person have

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

The correct answer is 10%