IQ of a person is given by the formula

,

Where MA is mental age and CA is chronological age. If 80 ≤ IQ ≤ 140 for a group of 12 years old children, find the range of their mental age.

Chronical age = CA = 12 years

IQ for age group of 12 is 80 ≤ IQ ≤ 140.

Let MA denote Mental Age

80 ≤ IQ ≤ 140

Putting

⇒ 9.6 ≤ MA ≤ 16.8

∴ Range of mental age of the group of 12 years old children is

9.6 ≤ MA ≤ 16.8