An investment of $5000 was made in a certain account and earned interest that was compounded annually. The annual interest rate was fixed for the duration of the investment, and after 12 years the $5000 increased to $20000 by earning interest. In how many years after the initial investment was made the $5000 have increased to $40000 by earning interest at that rate?	Choose the correct choice from the following answers
A) 16
B) 12
C) 20
D) 24
E) 18
In 12 years the investment quadrupled (from $5,000 to $40,000).   Thus, at the same rate compounded annually, it would need additional   12/2= 
<gadget id="calculator">  12/2</gadget>
<output>6</output>
6 years to double (from $20,000 to $40,000).   Therefore, 12+6=18 years are needed $5,000 to increase to $40,000.   Answer: 18.
<result>E</result>
An investment of $5000 was made in a certain account and earned interest that was compounded annually. The annual interest rate was fixed for the duration of the investment, and after 12 years the $5000 increased to $20000 by earning interest. In how many years after the initial investment was made the $5000 have increased to $40000 by earning interest at that rate?