To represent the scenario where Verizon charges $35 per month for unlimited data and a $90 service fee, you can use the following equation:
Total cost (C) = (Monthly data cost) × (Number of months) + Service fee
C = ($35/month) × (12 months) + $90
Now, calculate the total cost for 12 months:
C = $420 + $90
C = $510
So, John has paid Verizon a total of $510 over 12 months for the unlimited data plan and the service fee.
Conclusion: John has paid Verizon a total of $510 over 12 months for his unlimited data plan, including the monthly data cost and the service fee.