A man arranges to pay off a debt of ₹36000 by 40 annual instalments which form an AP. When 30 of the instalments are paid, he dies, leaving one - third of the debt unpaid. Find the value of the first instalment.

Given: -


Total debt = Rs.36000


A man pays this debt in 40 annual instalments that forms an A.P.


After annual instalments, that man dies leaving one - third of the debt unpaid.


So,


Within 30 instalments he pays two - thirds of his debt.


Sum of n terms in an Arithmetic Progression =


He has to pay 36000 in 40 annual instalments,



Where,


a = amount paid in the first instalment,


d = difference between two Consecutive instalments.


He paid two – a third of the debt in 30 instalments,



From equations (1) & (2)we get,


a = 510 & d = 20


The value of the first instalment is Rs.510.


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