A man borrowed a certain sum and agrees to repay it by paying ₹4000 at the end of first year and ₹7700 at the end of second year. If the rate of compound interest compounded annually is 10% per annum, then find the sum (in ₹) borrowed.

10000

10% = \(\frac{1 }{10}\)

Ratio of Sum and amount for 2nd year = 10  :  11

ATQ,

11R = 7700

1R = 700

So , Sum left after 1st year = 10R = 10 × 700 = 7000

Total amount at end of 1st year = 7000 + 4000 = 11000

Now ,

Ratio of initial sum and amount after 1st year  = 10  :  11

ATQ ,

11R = 11000

1R = 1000

Initial invested sum = 10R = 10 ×1000 = 10000