# Aptitude Question ID : 94158

If average of 20 observations $x_{1}, x_{2}, ...., x_{20}$ is y, then the average of $x_{1} - 101, x_{2} - 101, x_{3} - 101, ...., x_{20} - 101$ is:
[A]$101y$
[B]$20y$
[C]$y - 101$
[D]$y- 20$

$\mathbf{y - 101}$
Required average =
$= \frac{x_{1}+x_{2}+......+x_{20}}{20} - \frac{101\times 20}{20}$
$= y - 101$
Hence option [C] is the right answer.