Question

a man arranges to pay off a debt of rupees 36000 by 40 monthly instalments which form an arithmetic series. When 30 of the instalments were paid he died leaving one- third of the debt unpaid. Find the value of the first instalment

Answer 1

first installment = a
common difference between any two consecutive installments =d
Using the formula for the sum of an A.P.
S=n/2 [2a+(n−1)d]
3600=40/2 [2a+(40−1)d]
180= 2a+39d
                             And
2400=30/2 [2a+(30−1)d]
160=2a+29d
On solving The above equations we get
d=2 and a=51
Value of 8th installment= 51+(8−1)2 = Rs 65

Answer 2

Answer:

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Soham Patil.