Determine the time for which Tom used his cell phone beyond the 800 minutes.
![860-800=60](https://img.qammunity.org/2023/formulas/mathematics/college/dkqwjhwsnxmhlj1twpp17voc4ud3w4fxaa.png)
Determine the charge for additional 60 minutes with taking 0.22 for one minute.
![60\cdot0.22=13.2](https://img.qammunity.org/2023/formulas/mathematics/college/tn55ziwz9gpsqzcpr9agx4gppl420i08r4.png)
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.
![\begin{gathered} C=79.99+13.2 \\ =93.19 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/ffbgmjbpo54d29pbp5n6e3n26fthyhtaxd.png)
So total cost to Tom for the cell phone is $93.19.