Jones invested a certain sum of money in a simple interest bond whose value grew to $500 at the end of 3 years and to $ 800 at the end of another 4 years. What was the rate of interest in which he invested his sum?  Choose one:
A) 12%	B) 12.5%	C) 16.67%	D) 16.25%	E) 18.18%
Lets assume the Principal Amount (initial amount invested) to be P   rate of interest to beRand time as T. We need to find R   Now After a time of 3years the principal P amounts to $500 and after a time of 7years ( question says after another 7years so 3+4) P becomes $800.   Formulating the above data   Amount (A1) at end of 3years   A1= P(1 + 3R/100) = 500   Amount (A2) at end of 7years   A2 = P(1 + 7R/100) = 800   Dividing A2 by A1 we get   (1 + 7R/100)/(1 + 3R/100) = 8/7   after cross multiplication we are left with 11R =100*2 which gives R = 18.18%   Option: 18.18%
<result>E</result>
Jones invested a certain sum of money in a simple interest bond whose value grew to $500 at the end of 3 years and to $ 800 at the end of another 4 years. What was the rate of interest in which he invested his sum?