Question

If some amount of money is invested in compound interest and the interest of second year is 880 rupees and the interest of third year is 968 rupees then what is the amount of principal and annual rate of interest

Answer 1

Step-by-step explanation:

GiVen:

CI for 2nd year = Rs 880

CI for 3rd year = Rs 968

So,

SI for Rs 880 per year = 968 - 880 = 88

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AnSwer:

★ Rate of interest = 88 × 100/ 880×1 = 10 %

Let original money be x.

Now,

★ Amt. after 2 years - Amt. after 1 year = CI for 2nd year.

\begin{gathered}\sf \implies \: x {(1 + \dfrac{10}{100} )}^{2} - (1 + \dfrac{10}{100}) = 880 \\ \\ \sf \implies \: x\bigg \{ ({ \dfrac{11}{10} )}^{2} - \dfrac{11}{10}\bigg \} = 880 \\ \\ \sf \implies \: x \bigg \{ \frac{121}{100} - \dfrac{11}{10} \bigg \} = 880 \\ \\ \sf \implies \:x \times \dfrac{11}{100} = 880 \\ \\ \sf \implies \:x = 8000\end{gathered}⟹x(1+10010)2−(1+10010)=880⟹x{(1011)2−1011}=880⟹x{100121−1011}=880⟹x×10011=880⟹x=8000

Therefore, rate of interest is 10 % and original money is Rs 8000.

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hope it will help you!!