AMC 10 2000 Problem 4

Chandra pays an on-line service provider a fixed monthly fee plus an hourly charge for connect time. Her December bill was \$ 12.48, but in January her bill was \$ 17.54 because she used twice as much connect time as in December. What is the fixed monthly fee?

Answer Choices
A. \$ 2.53
B. \$ 5.06
C. \$ 6.24
D. \$ 7.42
E. \$ 8.77