To analyze the relationship between the amount of money the student makes and time in days, we can look at the points given: (0, 20), (1, 30), and (2, 40).
- At day 0, the student makes $20.
- At day 1, the student makes $30 (which is $10 more than the previous day).
- At day 2, the student makes $40 (which is again $10 more than the previous day).
From this data, we can see that the student's earnings increase by $10 for each additional day they watch the dog. This suggests a linear relationship.
Now, let's interpret the points:
- The starting fee (intercept) is $20 (the amount made at day 0).
- The daily charge (slope) is $10 (the increase in fee per day).
Therefore, we can construct the fee structure:
- The student charges an initial fee of $20 plus $10 for each day of service.
Given these interpretations, the correct statement is:
C. The student charges $20 plus an additional $10 per day.