The question states that 'Goods purchased for Rs.15000' means that goods have been purchased for cash. Whenever goods or anything is purchased on credit, the party from whom goods are purchased is always mentioned. In the given question, no name is given, hence it is a cash purchase.
In the Accounting Equation two entries will be made on the Asset side. Cash will be reduced by Rs.15000 and Rs.15000 will be added in stock.