Question

Gopal has a cumulative deposit account and deposits Rs 900 per month for a period of 4 years. If he gets Rs 52,020 at the time of maturity, find the rate of interest.

Answer 1

Instalment per month P= Rs. 900
no of months n = 48
Let rate of interest r = r% p.a.

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

$=900\times \frac{48(48+1)}{2\times 12}\times \frac{r}{100}$

$=900\times \frac{2352}{24}\times \frac{r}{100}$

$=882r$

Maturity value $=(900\times 48)+\left(882\right)r$

given Maturity value = Rs.52,020

then

$(900\times 48)+\left(882\right)r=52,020$

$\left(882\right)r=52,020-43,200$

$\left(882\right)r=8,820$

$r=\frac{8,820}{882}$

r = 10%

Answer:- the rate of interest is 10%