Question

Q.11 Find the C.I. for Rs. 20000 at the rate 20% per annum for 3 years.​

Answer 1

Answer:

The amount at the end of “n" years of Investing in compound interest,

A=P(1+r100)n

Here, the Principal P = 20,000, number of years n = 2, rate of interest r = 20%.

Therefore, Amount A=20000(1+20100)2=20000(3625) = Rs.28,800.

Compound Interest C.I. = Amount - Principal = 28,800 - 20,000 = Rs.8,800.

Answer 2

Answer:

$here \: p = 20000 \\ r = 20\% \\ t = 3yrs \: \\ \\ amount(a) = p (1 \ + \frac{r}{100} ) {}^{t} \\ = 20000 \times (1 \ + \frac{8}{100} ) {}^{3 } \\ = 20000( \frac{27}{25} ) {}^{3} \\ = \frac{20000 \times (27) {}^{3} }{25 \times 25 \times 25} \\ = \frac{32 \times (27) {}^{3} }{25} \\ = 25194.24 \: rs \\ \\ compound \: interest \: (c.i) = a - p \\ = 25194.24 - 20000 \\ = 5194.24 \\ \\ hence \: the \: compound \: interest \: is \: = 5194.24 \: rs \:$