Quiz

[Zahria]

At what rate of compound interest does an invested sum of money effectively double in 14 yrs?

[johnalex]

Use the 'Rule of 72' which takes just a couple of seconds and is uncannily accurate. Just divide 72 by 14 which gives you 5.14% Magic! (pinch of salt required)

http://www.investopedia.com/ask/answers/04/040 104.asp

[Gizmonster]

..... or you can just simply work it out:

Let initial investment = S
Let rate of compound interest = R (where R is expressed as follows : if interest = 5%, then R = 1.05 ..... etc).

Then we have S x R ^14 = 2 x S

R^14 = 2

R = 2^(1/14)

i.e. R = 1.050756639
....... rate of compound interest required = 5.0756639%

Ta daaa ........