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Section A has 45 students with mean marks 68; Section B has 15 students with mean marks 52. Which statement about the combined mean of all 60 students is correct?

Class 10Mean of Grouped DataStatistics and Probability
  • AIt is exactly 60, the average of 68 and 52
  • BIt is 56, closer to 52, because the smaller mean pulls harder
  • CIt is 64, closer to 68, because Section A has three times as many students
  • DIt is 120, the sum of the two means

Step-by-Step Solution

Combined mean . A weighted mean always lies between the two group means and sits nearer the mean of the LARGER group, so 64 (not 60) is right — the plain average 60 would only be correct if both sections had the same strength. Nothing pulls the result below 60 here, and adding two means has no meaning.
Answer: C) It is 64, closer to 68, because Section A has three times as many students

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