Determine the time for which Tom used his cell phone beyond the 800 minutes.
[tex]860-800=60[/tex]Determine the charge for additional 60 minutes with taking 0.22 for one minute.
[tex]60\cdot0.22=13.2[/tex]The additional charge is $13.2.
The basic cell phone charge is $79.99.
Determine the total cost to Tom for using cell phone for 860 minutes.
[tex]\begin{gathered} C=79.99+13.2 \\ =93.19 \end{gathered}[/tex]So total cost to Tom for the cell phone is $93.19.
