The mean of 100 students was 45. Later, it was discovered that the marks of two students were misread as 85 and 54 instead of 58 and 45. Find corre...

Question

The mean of 100 students was 45. Later, it was discovered that the marks of two students were misread as 85 and 54 instead of 58 and 45. Find correct mean.

Accepted Answer

Option c: 44.64. Solution: Step 1: Compute the original total sum. text{Wrong sum} = 100 x 45 = 4500 Step 2: Correct the sum. Wrong readings: 85 and 54 (sum = 139). Correct readings: 58 and 45 (sum = 103). text{Correct sum} = 4500 - 139 + 103 = 4500 - 36 = 4464 Step 3: Compute correct mean. text{Correct mean} = 4464/100 = 44.64 Note: The correct mean is 44.64 (Option C), not 68 (Option A). Hence, Option C is the correct answer.

The mean of $\displaystyle 100$ students was $\displaystyle 45$ . Later, it was discovered that the marks of two students were misread as $\displaystyle 85$ and $\displaystyle 54$ instead of $\displaystyle 58$ and $\displaystyle 45$ . Find correct mean.

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The mean of 100\displaystyle 100100 students was 45\displaystyle 4545. Later, it was discovered that the marks of two students were misread as 85\displaystyle 8585 and 54\displaystyle 5454 instead of 58\displaystyle 5858 and 45\displaystyle 4545. Find correct mean.