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The average marks secured by 36 students were 52. But it was discovered that 64 was misread as 46. What is the correct mean of marks?

1. 52.0
2. 52.5
3. 53.0
4. 53.5

Correct answer: 52.5

Solution

The value 64 was misread as 46, so the total marks were understated by 18. The incorrect total is 36 × 52 = 1872, so the correct total is 1872 + 18 = 1890. The correct mean is 1890 ÷ 36 = 52.5.

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