Sajal invests ₹600 per month for $2\dfrac{1}{2}$ years in a recurring deposit scheme of Oriental Bank of Commerce. If the bank pays simple interest at $6\dfrac{2}{3}$ % per annum, find the amount received by him on maturity.

Given,

P = ₹600

n = $2\dfrac{1}{2}$ years = 2.5 years = 24 months + 6 months = 30 months

r = 6 $\dfrac{2}{3}$ % = $\dfrac{20}{3}$

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

$\therefore I = 600\times \dfrac{30\times 31}{2 \times 12} \times \dfrac{\dfrac{20}{3}}{100}\\[1em] I = 600 \times \dfrac{930}{24} \times \dfrac{20}{300}\\[1em] I = 600 \times 38.75 \times 0.67\\[1em] I = ₹1,550$

Sum deposited = ₹600 x 30 = ₹18,000

Maturity value = Sum deposited + Interest = ₹18,000 + ₹1,550 = ₹19,550

Hence, Sajal got ₹19,550 at the time of maturity.