Question

When $10$ is subtracted from each of the given observation, the mean is reduced by $60$%. If $5$ is added to all the given observation, then what will be the mean?

• A. $25$
• B. $30$
• C. $60$
• D. $65$

Answer 1

The correct option is B $30$

Let the mean be $\overline{x}$
According to the question,
$\overline{x}-10=60$% of $\overline{x}$
$\overline{x}=25$
Now, each observation is increased by $5$.
$\therefore$ New mean $=\overline{x}+5$
$=25+5=30$.