This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abnormalities of Development, Subject name: Pediatrics
A male child of 15 years with a mental age of 9 years has an IQ of: 
Select and explain. 
A. 50, B. 60, C. 70, D. 80
B: 60
Answer: B: 60 
Explanation: IQ = Mental age x 100/Chronological age =So, in this case, IQ = 9 x 100/15 = 60 Degree IQ level Mild 51-70 Moderate 36-50 Severe 21-35 Profound 0-20