Question

Vishal deposited $200$ per month for $5$ years in a recurring deposit account in a post office. If he received $13,830$ find the rate of interest.

Answer 1

Maturity Amount, $A=$ $13,830$, $P=$ $200$, $n=5\times 12=60$ months
Period, $N=\frac{1}{12}\left[\frac{n(n+1)}{2}\right]$ years
$=\frac{1}{12}\times 60\times \frac{61}{2}=\frac{305}{2}$ years
Amount Deposited $=Pn=200\times 60=$ $12,000$
Maturity Amount $=Pn+\frac{PNr}{100}$
$13830=12000+200\times \frac{305}{2}\times \frac{r}{100}$
$13830-12000=305\times r$
$1830=305\times r$
$\therefore$ $r=\frac{1830}{305}=6$%