Question

Mr. rk Nair gets Rs6455 at the end of one year at the rate of 14% per annum in a recurring deposit account. Find the monthly installment.

Answer 1

$\mathbf{Maturity Amount ( MA ) = Rs 6455} \\ \mathbf{ Number\: of\: months ( time \: or \: n ) = 1 × 12 months = 12 \: months} \\ \mathbf{ Rate ( r ) = 14\%}$




$\bold{ We \: Know, Maturity \: Amount =Pn + Interest}$




Hence,


$\bold{ 6455 = (12 \times P) + \frac{P \times n \times (n + 1)}{2 \times 24} \times \: \frac{14}{100} } \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: (Interest \: = \frac{P\times n \times (n + 1)}{2 \times 24} \times \frac{r}{100} ) \\ \\ \\ = >6455 = 12 P + \frac{13P \times 7}{100} \\ \\ \\ = > 6455 = \frac{1200P + 91P}{100} \\ \\ \\ = > \frac{6455 \times 100}{1291} = P \\ \\ \\ => 500 = P$




Hence, P = ₹500




$\mathbf{P = Principal = Monthly \: Instalment = Rs500}$

Answer 2

Maturity amount = Rs 6455



We Know, Maturity amount = pn + I


Hence,


6455 = pn + I


=> 6455 = ( p × 12 ) + [ p × 12 × 13 × 14 ] / ( 2 × 12 × 100 )


=> 6455 × 100 = 1200p + 91p


$= > \frac{6455 \times 100}{1291} = p$


=> 500 = p







Monthly Instalment = ₹ 500