A man borrowed some money from a private organisation at 5% simple interest per annum. He lended 50% of this money to another person at 10% compound interest per annum and thereby the man made a profit of Rs. 3205 in 4 years. The man borrowed

Let the borrowed amount be P. At 5% simple interest for 4 years, interest payable = P × 5 × 4 / 100 = 0.2P. The man lends 50% of P (i.e., 0.5P) at 10% compound interest for 4 years. Using CI formula: Amount = 0.5P(1 + 10/100)^4 = 0.5P(1.1)^4 = 0.5P × 1.4641 = 0.73205P. Compound interest earned = 0.73205P - 0.5P = 0.23205P. Profit = CI earned - SI payable = 0.23205P - 0.2P = 0.03205P = Rs. 3205. Therefore, P = 3205 / 0.03205 = Rs. 1,00,000.