A cell phone carrier charges a fixed monthly fee plus a constant rate for each minute used. Part 1. In January, the total cost for 125 minutes was $ 67.5 while in February, the total cost for 400 minutes was $ 95 . The constant charge for each minute used is:

a. 0.1

b. 0.12

c. 0.11

Part 2. The fixed montly fee charged by the carrier is; fee = $