Bhanu borrowed a sum of money from Siddhu at the rate of 9% for 2 years. Later he borrowed an additional sum of money at the rate of 10% for another three more years. If the ratio of the principal amount borrowed is 2 : 6 and the total interest received by Siddhu is Rs. 8100 then what was the total amount paid by Bhanu to Siddhu?

Let the amounts borrowed be 2x and 6x. First loan: 2x at 9% for 2 years = 2x × 0.09 × 2 = 0.36x. Second loan: 6x at 10% for 3 years = 6x × 0.10 × 3 = 1.8x. Total interest = 0.36x + 1.8x = 2.16x = Rs 8100, so x = 8100/2.16 = 3750. Total principal = 2x + 6x = 8x = 8 × 3750 = Rs 30000. Total amount = Principal + Interest = Rs 30000 + Rs 8100 = Rs 32100.