Multiple choice

The average marks obtained by 25 students of class A is 47, that of 35 students of class B is 51 and that of 30 students of class C is 53. The average score of the three classes is

  1. 50.55

  2. 50

  3. 49.55

  4. 49
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A Correct answer
Explanation

Weighted average = (25*47 + 35*51 + 30*53) / (25 + 35 + 30) = (1175 + 1785 + 1590) / 90 = 4550 / 90 = 50.555...

AI explanation

The total marks for class A is 25 times 47, giving 1175. The total marks for class B is 35 times 51, giving 1785, and the total marks for class C is 30 times 53, giving 1590. The overall average is the combined sum divided by the total students, which is 1175 plus 1785 plus 1590, resulting in 4550 divided by 90, equal to 50.55.

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