Question

find the compound interest for 21 by 2 years and 4000 at 10% per annum if the interest compounded yearly​

Answer 1

Correct Question :

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Find the compound interest for 2½ years of Rs. 4000 at 10% per annum if the interest compounded Yearly.

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AnswEr :

• Principal = Rs. 4000
• Rate = 10% p.a.
• Time = 2½ Years.

• First We will Take 2 Years :

$\mathsf{A = P \bigg( 1 + \dfrac{r}{100} \bigg) ^{n} }$

Where A = Amount and n = number of years

$\mathsf{A = 4000 \times \bigg( 1 + \dfrac{10}{100} \bigg) ^{2} }$

$\mathsf{A = 4000 \times \bigg( \dfrac{11}{10} \bigg) ^{2} }$

$\mathsf{A = 40 \cancel{00} \times \dfrac{121}{\cancel{100}} }$

$\mathsf{A = 40 \times 121 }$

$\mathsf{A = Rs. \: 4840}$

The Amount after two years = Rs 4840

Now that will be New Principal = Rs 4840

• Simple interest for last ½ year :

$\mathsf{SI = \dfrac{PRT}{100}}$

$\mathsf{SI = \dfrac{ \cancel{4840} \times \cancel{10} \times \frac{1}{\cancel2} } {\cancel{100}}}$

$\mathsf{SI = Rs. \: 242}$

• Amount after 2½ year :

⇒ Rs 4840 + Rs 242

⇒ Rs 5082

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⇒ C.I. = A - P

⇒ C.I. = Rs. 5082 - Rs. 4000

⇒ C.I. = Rs. 1082

∴ The compound interest is Rs 1082.