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Ruchi invested Rs. 1600 at the rate of compound interest for 2 years. She got Rs. 1764 after the specified period. Find the rate of interest.

 

Option: 1

5%


Option: 2

3%


Option: 3

7%


Option: 4

10%


Answers (1)

best_answer

Here, $\mathrm{P}=\mathrm{R} 1600, n=2$ years, $\mathrm{A}=\mathrm{R} 1764$
Now, according to the formula,
$ \text { Amount }=\mathrm{P}\left(1+\frac{R}{100}\right)^n$
$1764=1600\left(1+\frac{R}{100}\right)^2$
$\Rightarrow \quad \frac{1764}{1600}=\left(\frac{100+R}{100}\right)^2 \quad \Rightarrow \quad\left(\frac{21}{20}\right)^2=\left(\frac{100+R}{100}\right)^2$
$\Rightarrow \quad \frac{100+R}{100}=\frac{21}{20} \quad \Rightarrow \quad 100+\mathrm{R}=\frac{21}{20} \times 100$
$\Rightarrow 100+R = 105$
$\therefore R = 105-100 = 5%$
 

Posted by

Suraj Bhandari

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