Question

a child with a mental age of 9 and a chronological age of 12 has an iq of ______.
a) 50
c) 129
b) 75
d) 140

Explanation:

Step1: Recall IQ formula

IQ = $\frac{\text{Mental Age}}{\text{Chronological Age}} \times 100$

Step2: Plug in given values

Substitute Mental Age = 9, Chronological Age = 12
$\text{IQ} = \frac{9}{12} \times 100$

Step3: Calculate the result

Simplify $\frac{9}{12}=0.75$, then $0.75 \times 100 = 75$

Answer:

B) 75