Question

Ritu has Recurring Deposit Account in a bank and deposits Rs 80 per month for 18 months. Find the rate of interest paid by the bank if the maturity value of this account is Rs 1,554.

Answer 1

P=Rs80
n= 18
r= r % p.a.

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

$=600\times \frac{18\times (18+1)}{2\times 12)}\times \frac{r}{100}$

$=80\times \frac{342}{24}\times \frac{r}{100}$

$=11.4r$

the amount that Pramod will get at the time of maturity = $P\times n+S.I$

$=(80\times 18)+11.4r$

given maturity = Rs. 1554
then

$(80\times 18)+11.4r=1554$

$11.4r=1554-1440=114$

$r=\frac{114}{11.4}=10\%$