Final answer:
The student worked a total of 11 hours.
Step-by-step explanation:
To find the total number of hours worked, we need to add up the given hours:
1 1/2 + 2 3/4 + 3 3/4 + 5 1/2 = 1 1/2 + 2 + 3 + 5 = 11 hours.
Therefore, the student worked a total of 11 hours.