A parking garage charges a flat entry fee plus an hourly rate. Three hours of parking costs 18, and one hour costs 1 more than the flat…

The second equation is $y + x = x + 1$. Subtract $x$ from both sides and the $x$ terms cancel, leaving $y = 1$, so the hourly rate is $1, choice F. Substituting into the first equation gives $3(1)+x=18$, so the flat fee is $x=15$, and both equations check: $3(1)+15=18$ and $1+15=15+1$. The other choices all fail the second equation, because that equation forces $y=1$ regardless of $x$. Choices G ($3$), H ($8.5$), and J ($17$) would each require a different flat fee in the first equation, but none of those values can satisfy $y+x=x+1$. Notice that no solving for $x$ is needed to answer the question.