The blue cat stationery store bought several balls at the wholesale price of 1.5 yuan, and the retail price was 2 yuan each. When 20 balls were left, the profit was 150 yuan after deducting the cost of the purchase money. How many balls did the stationery store buy in total?
蓝猫文具店按批发价买进1.5元的皮球若干个，零售价每个2元，卖剩20个皮球时，计算买的钱除掉成本还获利润150元．文具店一共买进皮球多少个？
<gadget id="calculator">2 * 20</gadget>
<output>40</output>

<gadget id="calculator">40 + 150</gadget>
<output>190</output>

<gadget id="calculator">2 - 1.5</gadget>
<output>0.5</output>

<gadget id="calculator">190 / 0.5</gadget>
<output>380</output>

<result>380</result>