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# Mean of 10 items was found to be 15. On verification it was found that an item 21 was miscopied as 12. Find the correct mean.

$\begin {array} {1 1} (A)\;15 & \quad (B)\;15.3 \\ (C)\;15.9 & \quad (D)\;15.20 \end {array}$

Ans : (C)
Observed sum of 10 items = $15 \times 10$
$= 150$
Corrected sum = $150 -12 + 21$
$= 159$
Correct mean = $\large\frac{159}{10}$
$= 15.9$