This year's "Double 11" day, the "Starlight Office" stationery online store sold a total of 200 student pens for a total of 2470 yuan. In the first 8 hours, he sold 35 sticks at a profit price of 4 yuan each; in the next 16 hours, he sold 165 sticks at a profit price of 20% of the cost. How much does each pen cost?
今年"双11"那天，"星光办公"文具网店共去卖出200支学生钢笔，共售得2470元．前8小时，他按每支4元的利润定价售出了35支；后16小时，按成本的20%的利润定价卖出165支．这种钢笔每支的成本是多少元．
<gadget id="calculator">35 * 4</gadget>
<output>140</output>

<gadget id="calculator">2_470 - 140</gadget>
<output>2_330</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) * 165</gadget>
<output>33</output>

<gadget id="calculator">35 + 165 + 33</gadget>
<output>233</output>

<gadget id="calculator">2_330 / 233</gadget>
<output>10</output>

<result>10</result>