Question

Find the principal when:
final amount is $Rs.2420$ at $4\%$ per annum for $2\frac{1}{2}$ years.

Answer 1

$Amount\left(A\right)=Rs.2420$
$Rate\left(R\right)=4\%$ p.a.
$Time\left(T\right)=2\frac{1}{2}=\frac{5}{2}$ years
Let principal $=Rs.100$
Then $S.I.=\frac{PRT}{100}=\frac{100\times 4\times 5}{100\times 2}=Rs.10$
Amount = P + S.I. $=Rs.100+Rs.10=Rs.110$
If amount is $Rs.110$ then principal $=Rs.100$
If amount is $Rs.2420,$ then principal
$=\frac{100\times 2420}{110}$
$=Rs.2200$