Dr. Long sells a batch of clothing, priced at 20% of the profit. When 75% and 25 pieces of this batch of clothing are sold, in addition to recovering the cost, 50% of the estimated profit is also obtained, so how many pieces of this batch of clothing are there?
龙博士销售一批服装，按获利20%定价．当售出这批服装的75%又25件时，除收回成本外，还获得预计利润的50%，那么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>