Subject: mathqa
Question: peter invested a certain sum of money in a simple interest bond whose value grew to $ 400 at the end of 3 years and to $ 600 at the end of another 2 years . what was the rate of interest in which he invested his sum ?
Option: 
A: 25 %
B: 100 %
C: 67 %
D: 12.5 %
Answer: B