Question

If the compound interest earned on some sum for 2 years compounded annually at the rate of 12% is Rs.5088. What is the sum (Principal Amount)?

Answer 1

$\sf\large\underline{Let:}$

$\rm{\implies The\:sum\:be\:P}$

$\sf\large\underline{To\:Find:}$

$\rm{\implies Principal\:and\: Amount=?}$

$\sf\large\underline{Solution:}$

• By applying formula to calculate A and P]

$\sf\large\underline{Given:}$

$\rm{\implies Compound\: interest=Rs.5088}$

$\rm{\implies Time=2\: years}$

$\rm{\implies Rate=12\%}$

$\sf\large\underline{Formula\: used:}$

$\tt{\implies CI=P\bigg(1+\dfrac{r}{100}\bigg)^n-P}$

$\tt{\implies 5088=P\bigg(1+\dfrac{12}{100}\bigg)^2-P}$

$\tt{\implies 5088=P\bigg(\dfrac{112}{100}\bigg)^2-P}$

$\tt{\implies 5088=P\bigg(\dfrac{28}{25}\bigg)^2-P}$

$\tt{\implies 5088=\dfrac{784P}{625}-P}$

$\tt{\implies 5088=\dfrac{784P-625P}{625}}$

$\tt{\implies 5088=\dfrac{159P}{625}}$

$\tt{\implies 159P=3180000}$

$\tt{\implies P=Rs.20000}$

• Now calculate Amount here]

$\tt{\implies A=P+CI}$

$\tt{\implies A=20000+5088}$

$\tt{\implies A=Rs.25088}$

$\sf\large{Hence,}$

$\bf{\implies Principal=Rs.20000}$

$\bf{\implies Amount=Rs.25088}$

Answer 2

Given:

ci=5088

t=2years

r=12%

ci=p(1+r/100)^n-p

by solving we get heree

p=20000

A=p+ci

A=20000+5088=25088