Answer to long to fit here in details.

Question

One's intelligence quotient, or IQ, varies directly as a person's mental age and inversely as that person's chronological age. A person with a mental age of 22 and a chronological age of 20 has an IQ of 132. What is the chronological age of a person with a mental age of 25 and an IQ of 100?

Answer 1

"IQ" = k ("MA")/"CA" is an equation relating IQ, MENTAL AGE (MA) & CHRONOLOGICAL AGE (CA), using the stated variations.

 

using the data contained in the second sentence: 132 = k(22)/20 so k = 120.

 

Now we substitute the data from the third sentence:  100 = 120(25)/"CA"

 

Therefore "CA" = 30