Question

(3) Dattu borrowed 12.800 from a bank for 3 years at the rate of 12, p.c.p.a. at compound interest. What amount
must he pay back to the bank at the end of 3​

Answer 1

Solution!!

The concept of compound interest (CI) has to be used here. The principal, rate of interest and time is given in the question. According to the question, we have to find the amount.

Principal (P) = Rs 12,800

Rate of interest (R) = 12%

Time (n) = 3 years

Amount = P(1 + (R/100))ⁿ

Amount = 12800(1 + (12/100))³

Amount = 12800(120/100)³

Amount = 12800(12/10)³

Amount = 12800 × (1728/1000)

Amount = 12.8 × 1728

Amount = Rs 22,118.4

Abbreviations used:-

P → Principal

R → Rate of interest

n → Time

SI → Simple interest

The questioner may ask you to find compound interest too. So, here's how you can do that.

Compound interest (CI) = Amount - Principal

Answer 2

$\bold \orange{Given}\rightarrow$

Principal = 12800

Rate = 12 p.c.p.a.

Time = 3 years

Note:

Using the Information given in the question we have to find Amount of 3 years.

$\Large\bold\red {solution}$

$A = P (1+\frac{R}{100})\footnotesize ^ T$

$A = 12800 (1+\frac{12}{100})\footnotesize ^ 3$

$A = 12800 (\frac{100+12}{100})\footnotesize ^ 3$

$A = \frac{12800 \times 112 \times 112 \times 112}{100 \times 100 \times 100}$

$A = \frac{32 \times 112 \times 112 \times 28}{25 \times 25}$

$A = \frac{11239424}{625}$

$A = 17983.0784$

$\large \bold \orange{Ans}\Rightarrow$

Dattu must pay 17983.0784 rupees at the end of 3 years.