Radha deposited ₹ 400 per month in a recurring deposit account for 18 months. The qualifying sum of money for the calculation of interest is :

1. ₹ 3600

2. ₹ 7200

3. ₹ 68,400

4. ₹ 1,36,800

A person deposit ₹P, every month for n months at R percent per annum, simple interest in a recurring deposit account.

Assertion (A): The maturity value is more than total amount deposited by the person.

Reason (R): Maturity value includes an interest equal to $\dfrac{\text{P} \times \text{n(n + 1)} \times \text{R}}{2400}$

1. Assertion (A) is true, but Reason (R) is false.

2. Assertion (A) is false, but Reason (R) is true.

3. Both Assertion (A) and Reason (R) are correct, and Reason (R) is the correct reason for Assertion (A).

4. Both Assertion (A) and Reason (R) are correct, and Reason (R) is incorrect reason for Assertion (A).

Rohana has a recurring deposit account in State Bank of India. She deposits ₹ 800 per month for $2\dfrac{1}{2}$ years. Bank pays interest at the rate of 5% p.a.

Assertion (A): Interest earned by Rohana in $2\dfrac{1}{2}$ years is ₹ 1,650.

Reason (R): Interest earned = $P \times \dfrac{\text{n(n + 1)}}{2 \times 12} \times \dfrac{\text{r}}{100}$

where, P = monthly instalment, n = number of installments and r = rate of interest p.a.

1. Assertion (A) is true, but Reason (R) is false.

2. Assertion (A) is false, but Reason (R) is true.

3. Both Assertion (A) and Reason (R) are correct, and Reason (R) is the correct reason for Assertion (A).

4. Both Assertion (A) and Reason (R) are correct, and Reason (R) is incorrect reason for Assertion (A).

Dhruv deposits ₹600 per month in a recurring deposit account for 5 years at the rate of 10% per annum (simple interest). Find the amount he will receive at the time of maturity.