Question

25. A man repays a loan of Rs.65000 by paying Rs. 400 in the
first month and the increased payment of Rs.150 every month.
How long will it take him to clear the loan.​

Answer 1

n/2{2×20+(n−1)×15}=3250

n/2(40+15n−15)=3250

n(15n+25)=6500

15^2 +25n−6500=0

3n^2 +5n−1300=0

(n−20)(3n+65)=0

n=20 or, n=-65/3 --> 20 months

So, the answer is 20 months. It will take him 20 months to clear the loan.

Hope this helps.