A NBFC promised to lend money under simple interest but the NBFC included the interest every 6 months for calculating principal. If the bank had promised the rate of interest as 20% per annum and if a person took Rs. 15000 loan from the NBFC then how much interest he would have paid at the end of 1.5 years?

Promised simple interest at 20% p.a., but interest is added every 6 months (compounding semi-annually). Period 1 (0-6 months): Principal = 15000, Interest = 15000 × 20% × 1/2 = 1500. Period 2 (6-12 months): New principal = 16500, Interest = 16500 × 20% × 1/2 = 1650. Period 3 (12-18 months): New principal = 18150, Interest = 18150 × 20% × 1/2 = 1815. Total interest = 1500 + 1650 + 1815 = 4965. Option C matches.