If 2:4 is to 3:9, then 5:25 is to?

Answer: B. 20
The relationship is that the second number is the first number multiplied by itself. 2*2=4, 3*3=9, 5*5=25, so the answer is 20 (5*4).
Posted in:  Number Analogy -  Analogy -  Verbal Reasoning