Multiple choice

In a class of 20 students, in an examination of mathematics, 2 students scored 100 marks each, 3 got zero each and the average of the rest was 40. What is the average of the whole class?

  1. 32 marks

  2. 40 marks

  3. 48 marks

  4. None of these
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B Correct answer
Explanation

Total students = 20. 2 students scored 100 (sum = 200). 3 students scored 0 (sum = 0). Remaining 15 students have an average of 40 (sum = 15 * 40 = 600). Total sum = 200 + 0 + 600 = 800. Average = 800 / 20 = 40.

AI explanation

The total score of the 2 students is 200 marks and the remaining 15 students have an average of 40, giving them a total score of 600. The combined total marks for all 20 students is 200 plus 600, which equals 800. Using the basic average formula of total sum divided by number of items, 800 divided by 20 yields an overall class average of 40 marks.

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