The value of a flat worth ₹500,000 is depreciating at the rate of 10% per annum. In how many years will the value be reduced to ₹364,500?

Each year the value is multiplied by 0.9. The ratio 364500 / 500000 = 0.729, which equals 0.9 x 0.9 x 0.9, so the fall takes 3 years. Two years would leave 405000, which is still too high.