Joe invested a certain sum of money in a simple interest bond whose value grew to $400 at the end of 3 years and to $500 at the end of another 5 years. What was the rate of interest in which he invested his sum?	Choose the correct option
A) 4.76%  B) 5.88%  C) 6.33%  D) 7.75%  E) 8.33%
In 5 years, the value grew $100, so the simple interest was $20 per year.   In 3 years, the total interest was 3*$20 = $60   The principal is $400 - $60 3* 20= 
<gadget id="calculator">3* 20</gadget>
<output>60</output>
$60   The principal is $400 - $60 = 340.   The interest rate is $20/$340 400 -  60= 
<gadget id="calculator">400 -  60</gadget>
<output>340</output>
340.   The interest rate is $20/$340= 1/17 which is about 5.88%   The answer is 5.88%.
<result>B</result>
Joe invested a certain sum of money in a simple interest bond whose value grew to $400 at the end of 3 years and to $500 at the end of another 5 years. What was the rate of interest in which he invested his sum?