Let the service call fee be x and the hourly rate be r, then
we have that
[tex]x+r=65------------(1)[/tex]
and
[tex]x+2r=105---------------(2)[/tex]
Using the elimination method, and subtracting equation (1) from equation (2), we have
r = 40.
Substituting r = 40 into equation (1), we have
[tex]\begin{gathered} x+(40)=65 \\ \Rightarrow x=65-40=25 \end{gathered}[/tex]
Hence, the service call fee is $25
