Ashok deposits ₹ 3200 per month in a cumulative deposit account for 3 years at the rate of 9% per annum. Find the maturity value of this account.

Given,

P = ₹ 3200

r = 9%

Maturity value of recurring deposit = Total sum deposited + Interest on it

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

where n is time in months.

Time (n) = 3 years = 3 × 12 = 36 months.

Substituting values we get :

$= 3200 \times 36 + 3200 \times \dfrac{36 \times (36 + 1)}{2 \times 12} \times \dfrac{9}{100} \\[1em] = 115200 + 3200 \times \dfrac{36 \times 37}{24} \times \dfrac{9}{100} \\[1em] = 115200 + \dfrac{115200 \times 37 \times 9}{2400} \\[1em] = 115200 + 48 \times 37 \times 9 \\[1em] = 115200 + 15984 \\[1em] = 131184.$

Hence, maturity value = ₹ 131184.