SOLUTION: A sum of Rs.6240 is paid off in 30 instalments such that each instalment is Rs. 10 more than the proceeding instalment. the value of the 1st instalment is. (A)Rs=36 (B)Rs=30 (C)Rs

Algebra ->  Sequences-and-series -> SOLUTION: A sum of Rs.6240 is paid off in 30 instalments such that each instalment is Rs. 10 more than the proceeding instalment. the value of the 1st instalment is. (A)Rs=36 (B)Rs=30 (C)Rs      Log On


   



Question 269102: A sum of Rs.6240 is paid off in 30 instalments such that each instalment is Rs. 10 more than the proceeding instalment. the value of the 1st instalment is.
(A)Rs=36 (B)Rs=30 (C)Rs=60 (D) none of these.

Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
Break this problem up into different pieces & solve.
6240=30x+29/2(10+290)
1st. payment=x
2nd. payment=x+10
3rd. payment=x+20
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30th paynebt=x+290
Payment sum=30x+29/2(10+290)
The 30x is the total of the base payments.
The 29/2(10+290) is the sum of the increasing additional payments for the last 29 payments.
6240=30x+14.5*300
6240=30x+4350
30x=6240-4350
30x=1890
x=1890/30
x=$63 is the amount of the first payment.
Proof:
30(63+63+290)/2
30*416/2
15*416=6,240