Multiple choice

The average marks of $100$ students were found to be $40$. Later it was discovered that a score of $53$ was misread as $83$. Find the correct average corresponding to the correct score _______.

  1. $38.7$
  2. $39$
  3. $39.7$
  4. $41$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total sum = 100 * 40 = 4000. Correct sum = 4000 - 83 + 53 = 3970. Correct average = 3970 / 100 = 39.7.

AI explanation

The sum of the observed scores is 100 multiplied by 40, which is 4000. The correct score of 53 is 30 less than the misread score of 83, making the correct total sum 3970. Dividing this correct sum by 100 students gives the correct average of 39.7.

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