Answer: Felix paid for 11 months.
Step-by-step explanation:
Let x = Number of months
Given: Annual fee = $ 20
charge per month = $15
Total amount = Annual fee + (charge per month) x (number of months)
[tex]\Rightarrow\ 185 = 20+15x\\\\\Rightarrow\ 165=15x\\\\\Rightarrow\ x = \dfrac{165}{15}\\\\\Rightarrow\ x =11[/tex]
Hence, Felix paid for 11 months.