We have the following:
With the following options
[tex]\begin{gathered} A=90+10h \\ B=25h \end{gathered}[/tex]Where h is the number of hours
To know the same value we have to match both equations
[tex]\begin{gathered} 90+10h=25h \\ 25h-10h=90 \\ 15h=90 \\ h=\frac{90}{15} \\ h=6 \end{gathered}[/tex]it means that at 6 hours of work they charge the same amount