Question

The interest paid on a certain sum of money after 4year at a rate of 5% per annum was rs 840 find the principal borrowed and the amount returned
​

Answer 1

Answer:

principle is rs42 and amount is rs882

Answer 2

Answer:

Principal borrowed = ₹4200.

Amount returned = ₹5040.

Step-by-step explanation:

We've been given Time, rate, and Simple Interest.

We've to calculate principal and amount. At 1st we will calculate principal then amount. We can calculate Amount using two methods.

Calculating Principal

$\bf \: \: \: \: \: \: \: \: \: {S.I.=\dfrac{P \times R \times T}{100}}$

$\bf{:\implies{P= \dfrac{100 \times S.I.}{R\times\:T}}} \\ \\ \\\rm:\implies{P= \frac{ \cancel{100} \times\cancel{840}}{ \cancel5 \times \cancel4}} \\ \\ \\ \rm:\implies{P=20 \times 210} \\ \\ \\\rm\therefore{Principal=₹4200 \: \: \: \: }$

Calculating Amount Using 1st Method

Principal = ₹4200.

Simple Interest = ₹840.

Amount = ?

$\:$

A = P + S.I.

= 4200 + 840

$\therefore$Amount = ₹5040.

Calculating Amount Using 2nd Method

Principal = ₹4200.

Time = 4years.

Rate = 5%.

Amount= ?

$\:$

$\bf\:A=P\bigg\lmoustache1+{\dfrac{R×T}{100}\bigg\rmoustache}$

$\:$

$:\implies\sf\:A=4200\bigg\lmoustache1+{\dfrac{\cancel5×\cancel4}{\cancel{100}}\bigg\rmoustache}$

$\:$

$:\implies\sf\:A=4200\bigg\lmoustache1+{\dfrac{1}{\cancel{5}}\bigg\rmoustache}$

$\:$

$:\implies\sf\:A=4200\bigg\lmoustache{\dfrac{5+1}{{5}}\bigg\rmoustache}$

$\:$

$:\implies\sf\:A=4200\bigg\lmoustache{\dfrac{6}{{5}}\bigg\rmoustache}$

$\:$

$:\implies\sf\:A=4200×\dfrac{6}{5}$

$\:$

$:\implies\sf\:A=840×6$

$\:$

$\therefore{\bf\sf{\: Amount=₹5040.}}$

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