Question

the principal of 4000 amount to 5324in 3years at compound interest. find the rate of intrest

Answer 1

Hope u like my process
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Let rate of interest be r

Prnicipal(P) = Rs 4000

Amount (A) = Rs 5324

Time (T) = 3yrs

By formula of Compound interest,

$= > a = p {(1 + \frac{r}{100} )}^{t} \\ \\ or. \: \: 5324 = 4000(1 + 0.01 \times r) ^{3} \\ \\ or. \: \: \frac{5324}{4000} = {(1 + 0.01 \times r)}^{3} \\ \\ or. \: \: \frac{1331}{1000} = {(1 + 0.01 \times r)}^{3} \\ \\ or. \: \: (1 + 0.01 \times r) = \sqrt[3]{ \frac{ {11}^{3} }{ {10}^{3} } } \\ \\ or. \: \: 1+ 0.01 \times r = \frac{11}{10} \\ \\ or. \: \: 0.01 \times r = 1.1 - 1 = 0.1 \\ \\ or. \: \: r = \frac{0.1}{0.01} = 10\%$
So rate of interest (R) = 10%

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