Final answer:
To determine the refund amount, subtract the amount paid by the student from the amount paid by Maria: (B/7.45 / 6) - (B/6.45 / 5).
Step-by-step explanation:
To determine the refund amount, we need to calculate the difference between the total amount paid by Maria and the total amount paid by the student.
Maria paid B/7.45 for 3 packages of bacon and 3 cartons of eggs. This means she paid B/7.45 / 6 (since there are 6 items in total).
The student paid B/6.45 for 2 packages of bacon and 3 cartons of eggs. This means he paid B/6.45 / 5 (since there are 5 items in total).
The refund amount can be calculated by subtracting the amount paid by the student from the amount paid by Maria: (B/7.45 / 6) - (B/6.45 / 5).