Answer :
Using the formula IQ = mental age / chronological age "/" 100, a 10-year-old boy testing at a 12-year-old level has an IQ of 120. Hence, the correct answer is option b. 120.
To determine the IQ of a 10-year-old boy who tests at a 12-year-old level, we use the formula:
IQ = mental age "/" chronological age "/" 100.
Given that:
Mental age = 12 years
Chronological age = 10 years
Plugging these values into the formula:
IQ = (12 "/" 10) "/" 100 = 1.2 "/" 100 = 120
Hence, the correct answer is option b. 120.
