A batch of commodities is priced according to the expected profit of 50%, but only 70% of the commodities are sold. In order to sell the remaining products as soon as possible, the store decides to sell the products at a discount, so that the profit obtained is 82% of the original expected profit. How much is the discount?
一批商品，按期望获得50%的利润来定价，结果只销掉70%的商品．为了尽早销掉剩下的商品，商店决定把商品打折出售，这样所获得的利润是原来期望利润的82%，问打了多少折扣？
<result>8</result>