Braun invested a certain sum of money at 8% p.a. simple interest for 'n' years. At the end of 'n' years, Braun got back 7 times his original investment. What is the value of n?
Choose the correct choice from the following:  A) 50 years  B) 25 years  C) 12 years 6 months  D) 37 years 6 months  E) 75 years
Explanatory Answer   Let us say Braun invested $100.   Then, at the end of 'n' years he would have got back $700.   Therefore, the Simple Interest earned = 700 - 100= 
<gadget id="calculator">700 - 100</gadget>
<output>600</output>
$600.   We know that Simple Interest= (Principal * number of years * rate of interest) / 100   Substituting the values in the above equation we get 600 = (100 * n * 8) / 100   Or 8n = 600   Or n = 75 years.   correct choice is (75 years)
<result>E</result>
Braun invested a certain sum of money at 8% p.a. simple interest for 'n' years. At the end of 'n' years, Braun got back 7 times his original investment. What is the value of n?