# Deepa Has a 4-year Recurring Deposit Account in a Bank and Deposits Rs 1,800 per Month. If She Gets Rs 1,08,450 at the Time of Maturity, Find the Rate of Interest. - Mathematics

Sum

Deepa has a 4-year recurring deposit account in a bank and deposits Rs 1,800 per month. If she gets Rs 1,08,450 at the time of maturity, find the rate of interest.

#### Solution

Installment per month(P) = Rs 1,800

Number of months(n) = 48

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

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

= 1800 xx (48(48 +1))/(2 xx 12) xx "r"/100

= 1800 xx 2352/24  xx "r"/100 = "Rs " 1764r

Maturity value = Rs (1,800 x 48) + Rs (1,764)r

Given maturity value = Rs 1,08,450

Then Rs (1,800 x 48) + Rs (1764)r = Rs 1,08,450

⇒ 1764r = Rs 1,08,450 – Rs 86,400

=> "r" = 22050/1764 = 12.5%

Concept: Computation of Interest
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#### APPEARS IN

Selina Concise Maths Class 10 ICSE
Chapter 2 Banking (Recurring Deposit Account)
Exercise 2 (B) | Q 7 | Page 24