A company charges for its internet service based on a linear model: a fixed monthly fee plus a charge per gigabyte (GB) of data used. Last month, a customer used 20 GB and was charged $45. This month, the same customer used 35 GB and was charged $60. Which of the following statements is true?
The fixed monthly fee is $1.
The charge per GB is $1.
The fixed monthly fee is $15.
The charge per GB is $2.
