Question

I.Q. of a person is given by $I=\frac{M}{C}\times 100$, where $M$ is mental age and $C$ is chronological age. If $80\le I\le 140$ for a group of $12$ years old children, then their mental age can be

• A. $10$
• B. $13$
• C. $14$
• D. $17$

Answer 1

Answer: (A), (B), (C)

$14$

$80\le \frac{M}{C}\times 100\le 140$
$\Rightarrow 8\le \frac{M}{12}\times 10\le 14$
$\Rightarrow 96\le 10M\le 168$
$\Rightarrow 9.6\le M\le 16.8$