1.

Jainil opens recurring deposit amount in the bank of rupees 400 per month how many installment does he have to pay to get a maturity of rupees 8560 if the bank pays the simple interest of 8% per annum

Answer»

Given :

The monthly deposit AMOUNT = P = Rs 400

The MATURITY value = A = Rs 8560

The rate of interest = R = 8% per annum

To Find :

The number of installments

Solution :

Let The number of installments = n

∵ Interest = P × \dfrac{n \times ( n + 1)}{2} × \dfrac{R \times T}{100}

Or,            = Rs 400 × \dfrac{n \times ( n + 1)}{2} × \dfrac{8 \times 1}{100 \times 12}

Or,            = 2.67  × \dfrac{n \times ( n + 1)}{2}

Again

Maturity value = money deposit + Interest

Or,  A = Rs 400 × n +  2.67  × \dfrac{n \times ( n + 1)}{2}

Or,  Rs 8560 = Rs 400 n +  2.67  × \dfrac{n \times ( n + 1)}{2}

Or,  2.67  × \dfrac{n \times ( n + 1)}{2} = 8560 - 400 n

Or,   \dfrac{n \times ( n + 1)}{2} = \dfrac{8560}{2.67} - 400 n

Or,  \dfrac{n \times ( n + 1)}{2} = 3205.9 - 400 n

Or,  n² + n = 6411.8 - 800 n

Or, n² + 801 n - 6411.8 = 0

Solving this quadratic equation

i.e   n = \dfrac{-801\pm \sqrt{(801)^{2}-4\times 1\times (-6411.8)}}{2\times 1}

∴    n = 7.9 ≈ 8 , - 808.9

Number of installment = n = 8

Hence, The number of installments that have to pay is 8  . Answer


Discussion

No Comment Found

Related InterviewSolutions