Final answer:
The correct answer to the student's question is option B, which is represented by the system of equations: c + a = 109 and c = a + 15.
Step-by-step explanation:
The student is trying to figure out which system of equations represents the situation where Carli and Angela share a cell phone plan with a total bill of $109, with Carli's share being $15 more due to going over her data limit. The correct system of equations need to account for both the total bill and the difference between Carli's and Angela's shares due to the overage charge.
Option B correctly represents this situation with the following two equations:
- The first equation c + a = 109 represents the total bill amount.
- The second equation c = a + 15 represents the fact that Carli's share (c) is $15 more than Angela's (a).
Therefore, the system of equations that correctly models this situation is: