Given that,
Jaspal singh takes total loan = Rs118000
He repays his total loan by paying every month.
His first installment = 1000
Second installment = 1000 + 100 = 1100
Third installment = 1100 + 100 = 1200 and so on
Thus, we have 1000, 1100, 1200, … which form an AP, with
first term, a = 1000
common difference, d = 1100 – 1000 = 100
nth term of an AP
So amount paid in 30 installments = sum of first 30 terms of this AP
= 15(2000 + 2900)
= 15(4900) = 73500
So he pays Rs 73500 in 30 installments
Loan left = total loan - paid lone
= 118000 - 73500 = 44500 Rs