What will be the intelligence quotient of a 15 year old boy, when his mental…
2022
What will be the intelligence quotient of a 15 year old boy, when his mental age is 12?
- A.
80
- B.
90
- C.
100
- D.
110
Attempted by 22 students.
Show answer & explanation
Correct answer: A
Concept: The intelligence quotient (IQ) is a ratio-based measure of cognitive development, defined as IQ = (Mental Age ÷ Chronological Age) × 100, where Mental Age (MA) is the age level at which a person is currently performing and Chronological Age (CA) is the person's actual age. A value below 100 means mental performance trails chronological age; a value above 100 means it leads.
Mental Age (MA) = 12 years and Chronological Age (CA) = 15 years, as given in the question.
Substitute into the formula: IQ = (12 ÷ 15) × 100.
Simplify: 12 ÷ 15 = 0.8, so IQ = 0.8 × 100 = 80.
Cross-check: Reversing the calculation confirms it — 15 × (80 ÷ 100) = 12, which matches the stated mental age, so IQ = 80 is consistent with both given ages.