A dealer sells a batch of clothing and sets the price according to the profit of 20%. When 75% and 25 pieces of this batch of clothing are sold, in addition to recovering the cost, he will also get half of the estimated profit. How many pieces of this batch of clothing are there?
某经销商销售一批服装，按获利20%来定价，当售出这批服装的75%又25件时，除收回成本外，还获得预计利润的一半，这批服装共有多少件？
<gadget id="calculator">30 - 10</gadget>
<output>20</output>

<gadget id="calculator">3_000 / 20</gadget>
<output>150</output>

<result>150</result>