Question

A man borrows RS. 1000 and agrees to repay with a total interest of Rs. 140 in 12 installments, each installment being less then the proceeding one by RS. 10. What should be his 1st installment

Answer 1

Let the First Instalment be 'a'.

and second Instalment be '10-a'.

Since it will form an A.P.

The sum of ten Instalments = 10/2[2a + (10-1) (-10)] = 5[2a - 90]

So, 5 [2a-90] = 4000.

=    10a - 450 = 4000.

      10a = 4450.

          a = 4450/10

          a = 445.

First Instalment will be Rs. 445.

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