# Chapter 3

## Chapter 3

• Submitted By: azikn
• Date Submitted: 07/01/2009 2:17 AM
• Words: 373
• Page: 2
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ASSIGNMENT # 2

Chapter # 3

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Submitted to:

Mr. Zia-ul-Haq Zuberi

Submitted by:

Azeem Fraz khan
MBA-13 (BBA Stream)

Dated: 20th April 09

Army Public College of Management Sciences
APCOMS

“Rule of 72” is a quick way to handle compound interest problems involving double your money. This rule states that if the number of years, n, that investment will be held is divided into the value 72, we will get the approximate interest rate, i, required for the investment to double value.
Same as if we get interest rate, i, we can also get number of years, n, at particular interest rate, i, by dividing it to the value 72.
It can be best illustrated with the help of example:
Suppose an investor invest Rs. 10 million in land and sold it after 5 years at price Rs. 20 million. At what rate, i, investor double his investment after 5 years?
Solution:
72/5 = 14.4%
14.4% is a rate at which investor double his investment.
Accuracy measure:
To see how accurate the result of “Rule of 72”, we use formula of future vale compounding interest rate that is:
FV = PV (1+i) n
Solution:
20,000,000 = 10,000,000 (1+i) 5
2 = (1+i) 5
(2) 1/5 = 1+i
1.148 = 1+i
i = 1.148 – 1
i = .148 = 14.8%
This 14.8% is accurate interest rate at which investor’s amount double to Rs. 20 million, which shows that by applying “Rule of 72” we only get nearest or approximate result but not accurate one.
Approximate result is found in case of finding n, number of year to double investor’s investment at specific interest rate, i.