The store buys a batch of clothes at a price of 120 yuan each, and the retail price is 150 yuan each. When there are 10 pieces left, the profit is 300 yuan. How many pieces of clothes are there in this batch?
商店以每件120元的价格购进一批衣服，零售价每件150元，当卖到还剩10件时，获利300元，这批衣服共有多少件？
<gadget id="calculator">150 * 10</gadget>
<output>1_500</output>

<gadget id="calculator">300 + 1_500</gadget>
<output>1_800</output>

<gadget id="calculator">150 - 120</gadget>
<output>30</output>

<gadget id="calculator">1_800 / 30</gadget>
<output>60</output>

<result>60</result>