First, you multiply 600 and .20 to find 20% of 600 rupees, which is 120 rupees. Second, you subtract the 20%, (120 rupees) from 600 rupees, which is 480 rupees. After that, you have the original selling price of 480 rupees that the man purchased the article for, but the question is stating that he gained 15% of the original sales price. So, you multiply 480 and .15 to find 15% of 480 rupees, which is 72. However, he GAINED more money than what he payed for the article so you add 72 rupees to 480 rupees to get 552 rupees. In conclusion, the man sells the article for 552 rupees.