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**The average of 9 observations was found to be 35. Later on, it was detected that an observation 81 was misread as 18. The correct average of the observation is.**

A. 28
B. 42
C. 32
D. 45
**Answer: Option B**

## Show Answer

Solution(By Apex Team)

$\begin{array}{l}\text{Difference = 81 – 18 = 63}\\
\text{So, change in average}\\
=+\frac{63}{9}\\
\text{ = + 7}\\
\text{Correct average = 35 + 7}=42\end{array}$