IBPS RRB Office Assistant Mains 7 Oct 2018 Paper

The following question has three statements. Study the question and the statements and decide which of the statement(s) is necessary to answer the question.
A departmental store sold a product for Rs. 1620. Find the cost price of the product.
I) The store marked the price of the product 35% above its cost price.
II) The product was sold at a discount of 20% on the marked price.
III) The store earned a profit of 8%.