Amit borrowed Rs. 6000 from the bank and returned Rs. 2000 after 6 years. After 10 years from starting he returned Rs. 6600 and settle his account. What is rate of interest?

5%

Total amount paid = 6600 + 2000 = 8600

SI   = 8600 - 6000 = 2600

\(\frac{6000 × R × 6}{100}\) + \(\frac{4000 × R × 4}{100}\)  = 2600

360 R + 160R = 2600

R = \(\frac{2600}{520}\) = 5%