Learning Math

In the article “The Number 72“, we learnt how to guesstimate the time required for an amount of money to double if invested at a defined rate of annual interest. Click here to access the article.

Then, we learnt about the number 114 in the article “Triple Your Money“, where we learnt about the time required for an amount of money to triple at a specified rate of interest. Click here to access the article. Picture Credit: commons.wikimedia.org

Now, in the last article in this series, we shall become aware of another power number – the number 144. And as the article suggests, it shall help guesstimate the time required for an amount to quadruple i.e., become 4 times its original value for a given rate of interest. And if you have followed the previous articles, you already know the formula:

(Number of years to quadruple) x (Rate of Interest p.a.) = 144

So, if you have a 1000 INR note, you know that it would become INR 4000 at 12% rate of interest in?

Yes, 12 years. Simple, isn’t it?

Hope you find this trick useful.

Note: This is an estimate to be used to make your life easier and does not give an answer accurate to the number of days. Also, the higher the expected rate of interest, the less accurate does the formula become but still you can use it safely!