Question

please answer the questions please and explain it also! if you want brainlist so answer questions please!for 20 points.​

Answer 1

Answer:

12.5 %

Step-by-step explanation:

${\underline{{\text{Given}}}}$

Principal (P) = Rs 102400

Amount (A) = Rs 145800

Time (t) = 3 yr

${\underline{{\text{To Find:}}}}$

Rate of compound Interest

${\underline{{\text{Solution:}}}}$

let, the rate of interest be x % per annum.

As we know,

$\boxed{A = P(1+\frac{r}{100})^{t}}$

Where, A = Amount

P = Principal

r = rate of interest

t = time

So,

${ 145800= 102400(1+\frac{x}{100})^{3}} \\ \\ \frac{145800}{102400} = (1+\frac{x}{100})^{3} \\ \\ \frac{1458}{1024} = (1+\frac{x}{100})^{3} \\ \\ \frac{729}{512} = (1+\frac{x}{100})^{3} \\ \\ {( \frac{9}{8} )}^{3} = (1+\frac{x}{100})^{3} \\ \\ \frac{9}{8} = 1+\frac{x}{100} \\ \\ \frac{9}{8} - 1 = \frac{x}{100} \\ \\ \frac{1}{8} = \frac{x}{100} \\ \\ x = \frac{100}{8} \\ \\ x = 12.5 \\ \\ \therefore \: \text{The required rate of interest is 12.5 \% per annum}$