bookstore sells a kind of wall calendar. It can make a profit of 18 yuan for each copy. After the sale (2/5), the price of each copy will be reduced by 10 yuan. If all are sold out, the total profit will be 3,000 yuan. How many copies of this kind of wall calendar does the bookstore sell? ?
某书店出售一种挂历，每出售一本可获利18元，出售(2/5)后，每本减价10元，全部售完，共获利3000元，这个书店出售这种挂历多少本？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) * 18</gadget>
<output>36/5 = around 7.2</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">18 - 10</gadget>
<output>8</output>

<gadget id="calculator">(3/5) * 8</gadget>
<output>24/5 = around 4.8</output>

<gadget id="calculator">(36/5) + (24/5)</gadget>
<output>12</output>

<gadget id="calculator">3_000 / 12</gadget>
<output>250</output>

<result>250</result>