# Rekha Opened Recurring Deposit Account for 20 Months. the Rate of Interest is 9% per Annum and Rekha Receives Rs. 441 as Interest at the Time of Maturity. Find the Amount Rekha Deposited Each Month. - Mathematics

Sum

Rekha opened a recurring deposit account for 20 months. The rate of interest is 9% per annum and Rekha receives Rs. 441 as interest at the time of maturity.
Find the amount Rekha deposited each month.

#### Solution

Let the monthly installment i.e P = Rs. x.
Since n = 20 months and r = 9%

∴ Interest       = P xx (n(n+1))/(2xx12) xx r/100

= (x xx 20 (21))/(2xx12) xx 9/100

 = (x xx20xx21 )/(2xx12) xx 9/100

 = (x xx 5xx7xx9)/(2xx100)

Interest    =  1.575 x Rs.
Interest = 441 {Given}

⇒ 1.575 x = 441

⇒ x = 280 Rs .

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