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The population of a country is 10 crore and it is the possibility that the population will become 13.31 crore in 3 yr. What will be the the annual rate per cent on this growth?

A) 8%
B) 12.7%
C) 10%
D) 15%

Correct Answer:



C) 10%

Description for Correct answer:

Given, P = 10 crore and population after 3 yr = 13.31 crore

According to the formula,

Population after n yr = \( \Large P \left(1+ \frac{R}{100}\right)^{n} \)

=> 13.31=\( \Large 10 \left(1+ \frac{R}{100}\right)^{3} \)

=> \( \Large \frac{1331}{1000} \)= \( \Large \left(1+ \frac{R}{100}\right)^{3} \)

=> \( \Large \left(\frac{11}{10}\right)^{3} \)=\( \Large \left(1+ \frac{R}{100}\right)^{3} \)

=> \( \Large 1+ \frac{R}{100} \)=\( \Large \frac{11}{10} \)

=> \( \Large \frac{R}{100}=\frac{11}{10}-1=\frac{1}{10} \)

R=10%

Part of solved Compound interest questions and answers : >> Aptitude >> Compound interest

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