Multiple choice

The average marks of 40 students in an English exam is 72. Later it is found that three marks 64, 62 and 84 were wrongly entered as 68, 65 and 73. The average after mistakes were rectified is-

  1. $28.5$
  2. $28.65$
  3. $28.72$
  4. $28.80$

  5. None of these
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Total = 40 × 72 = 2880. Correction: 68 → 64 (-4), 65 → 62 (-3), 73 → 84 (+11). Net change = +4. Corrected total = 2884, corrected average = 2884/40 = 72.1. None of the options (28.5, 28.65, 28.72, 28.80) match.

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