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144: Time to Quadruple

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.

144

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!

If you like this trick, like and share this article. Comment if you know more such tricks.

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Triple Your Money

In the post titled “The Number 72“, we learnt an useful formula – how to calculate the number of years required for a given amount of money to double at a specified rate of interest. Now suppose double is not cool enough for you. You want to know in how many years your money would triple!

Here, comes another number to help you estimate: 114.

114.png

Picture Credit: pt.wikipedia.org

You guessed it right, the formula is:

(Number of years to triple) x (Rate of Interest p.a.) = 114

So, now following the example in the previous article (click here to access it), if someone promises you a rate of return of 9%, know that your money would be doubled in approximately 12.67 years, i.e., 12 years and 8 months.

Do the math!

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!

If you like this trick, like and share this article. Comment if you know more such tricks.

The Number 72

72

Often we see investment advertisements which promise to double our money in (say) 9 years. Sounds good, doesn’t it?

Or don’t you wonder sometime, in how many years your money would double, if a Mutual Fund has been historically providing a return of 12%? Or, if you have INR 50 lacs, given the inflation rate of 8% (say), in how years would its value reduce by half in present terms?

(Answer to the three questions above are given at the end of the article.) 

The answer can be found out easily with a simple trick:

(Number of years to double) x (Rate of Interest p.a.) = 72

So, if someone promises you a rate of return of 9%, know that your money would be doubled in 8 years. If inflation is somewhere near 6%, know that your current kitty would be diminished by half in 12 years if not invested elsewhere.

Do the math!

If you like this trick, like and share this article. Comment if you know more such tricks.

Happy learning!

Answers: 8%; 6 years; 9 years. 

Picture Courtesy: https://in.pinterest.com/pin/53902526760366711/

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!