Question

Rishabh has a recurring deposit account in a post office for 3 years at 8% p.a. simple interest. If he gets Rs 9,990 as interest at the time of maturity, find:

(i) the monthly instalment.

(ii) the amount of maturity.

Answer 1

(i) Let instalment per month = P
No of months n=36
Rate of interest r = 8% p.a.

S.I = $P\times \frac{n(n+1)}{2\times 12}\times \frac{r}{100}$

$P\times \frac{36(36+1)}{2\times 12}\times \frac{8}{100}$

$=P\times \frac{1332}{24}\times \frac{8}{100}$

$=Rs.444P$

given interest = Rs. 9,990
then

$444P=9,990$

$P=\frac{9990}{444}=Rs.2,250$

P = Rs.2,250

so monthly instalment = Rs. 2,250

(ii) maturity value $=(2250\times 36)+9990=Rs.90,990$