Multiple choice

The mean of 100 items was found to be 40. If at the time of calculation two items were wrongly taken as 36 and 32 instead of 54 and 34, the correct mean is -

  1. 39.8

  2. 38.9

  3. 40.1

  4. 40.2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Original sum = 100 × 40 = 4000. Wrong values used: 36 + 32 = 68. Correct values should be: 54 + 34 = 88. Difference = 88 - 68 = 20. Correct sum = 4000 + 20 = 4020. Correct mean = 4020 ÷ 100 = 40.2.

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