Question 5

1. Determine the total number of students in the class ($N$):
   For any question, the sum of students who answered correctly, answered wrongly, and did not attempt equals the total class size:

   • From Question 1: $21 + 17 + 6 = 44$ students.
   • From Question 2: $15 + 27 + 2 = 44$ students.
   • From Question 3: $23 + 18 + 3 = 44$ students.
     Thus, $N = 44$ students in the class.

2. Calculate the total marks scored by all students:
   Marks are awarded only for correct answers (no negative or partial marking):

   • Question 1 (2 marks each): $21 \times 2 = 42$ marks.
   • Question 2 (3 marks each): $15 \times 3 = 45$ marks.
   • Question 3 (2 marks each): $23 \times 2 = 46$ marks.
   $$\text{Total Marks} = 42 + 45 + 46 = 133\text{ marks}.$$

3. Calculate the average marks per student:

   $$\text{Average} = \frac{\text{Total Marks}}{N} = \frac{133}{44} \approx 3.0227.$$

Rounding to two decimal places gives $3.02$, which matches option C.