Question

When $10$ is subtracted from all the observations, the mean is reduced to $60\text{\%}$ of its value. If $5$ is added to all the observations, then the mean will be

Answer 1

If $10$ is subtracted from all the observations, then mean will also get reduced by value of $10$.
Hence, $(\overline{x}-10)=\frac{3}{5}\overline{x}\Rightarrow \overline{x}=25$
Also $5$ is added to all the observations, then the mean will be $\overline{x}+5.$
Thus, the required mean $=25+5=30$