Average marks in Mathematics of Section A comprising 30 students is 65 and that of Section B comprising 35 students is 70. What are the average marks (approximately) of both the sections if it was detected later that an entry of 47 marks was wrongly made as 74?
- A. 67.28 ✓
- B. 67.58
- C. 68.11
- D. 68.63
Correct Answer: A. 67.28
Explanation
Initial total marks = (30 \times 65) + (35 \times 70) = 4400. The corrected sum adjusts the wrong entry: 4400 - 74 + 47 = 4373. The new average is \frac{4373}{65} \approx 67.28.
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