A store sells a batch of clothing at a price of 20% of the profit. When 75% and 25 pieces of this batch of clothing are sold, in addition to recovering the cost, half of the estimated profit is also obtained. How many pieces of this batch of clothing are there?
某商店销售一批服装，按获利20%定价．当售出这批服装的75%又25件时，除了收回成本外，还获得了预计利润的一半，求这批服装有多少件？
<gadget id="calculator">30 - 10</gadget>
<output>20</output>

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

<result>150</result>