A batch of commodities is priced according to the expected profit rate of 50%. As a result, only 70% of the commodities are sold, and the rest are sold at a discount. In this way, the total profit margin obtained is 82% of the expected rate.
一批商品按50%的期望利润率定价，结果只卖了70%的商品，剩下的打折出售，这样所得的全部利润率是所期望的82%，求打折商品定了几折后出售？
<result>8</result>