The shopping mall sells 1,000 exercise books with a cost of 2.5 yuan at a price of 40% of the profit. After 80% of the exercise books are sold out, the remaining exercise books are sold at a discount. After selling all the exercise books, the profit obtained is 93% of the expected profit. How much is the discount for the remaining exercise books?
商场将成本是2.5元的1000本练习本，按40%的利润定价出售，售完80%后，剩下的练习本打折销售，售完全部练习本，结果获得的利润是预计的93%，剩下的练习本打几折？
<result>9</result>