Interesting Rule of 72

I know most of you know this already(sorry to bore you guys !!) . Just writing it down for blog sake.

Anyway theres something called Rule of 72 which helps you a lot if you worry about your saved money.
The rule says to find out how quickly any money invested will double, simply divide 72 by the rate of interest you have invested.This is providing you dont touch the money and its grows in compounding nature.

Examples
If your money is invested at 8% it will double in 9 years (72 divided by 8)
If your money is invested at 10% it will double in 7.2 years (72 divided by10)