Mr Gulati Has a Recurring Deposit Account of Rs 300 per Month. If the Rate of Interest is 12% and the Maturity Value of this a - Mathematics

Sum

Mr Gulati has a Recurring Deposit Account of Rs 300 per month. If the rate of interest is 12% and the maturity value of this account is Rs 8,100; find the time (in years) of this Recurring Deposit Account.

Solution

Installment per month(P) = Rs 300

Number of months(n) = n

Let rate of interest(r)= 12% p.a.

:. "S.I" = "P" xx ("n"("n" + 1))/(2 xx 12) xx "r"/100

= 300 xx ("n"("n" + 1))/(2 xx 12) xx 12/100

= 300 xx ("n"("n" + 1))/24 xx 12/100 = "Rs " 1.5"n"("n" + 1)

Maturity value= Rs (300 × n)+ Rs 1.5n(n+1)

= Rs (300n+1.5n2+1.5n)

Given maturity value= Rs 8,100

Then 300n+1.5n2+1.5n = 8,100

=> 1.5^2 + 301.5"n" - 8100 = 0

=> "n"^2 + 201"n" - 5400 = 0

=> (n + 225)(n - 24) = 0

=> n = -225 or n = 24 months

Then time = 2 years.

Concept: Bank
Is there an error in this question or solution?

APPEARS IN

Selina Concise Maths Class 10 ICSE
Chapter 2 Banking (Recurring Deposit Account)
Exercise 2 (A) | Q 10 | Page 24