Xiaoqian spent a total of 12.4 yuan on notebooks and pens. Each notebook was 1.5 yuan, and each pen was 3.2 yuan. She bought 2 pens and how many notebooks did she buy?
小茜买笔记本和钢笔共花了12.4元，笔记本每本1.5元，钢笔每枝3.2元，买了2枝钢笔，买了几本笔记本？
<gadget id="calculator">3.2 * 2</gadget>
<output>6.4</output>

<gadget id="calculator">12.4 - 6.4</gadget>
<output>6</output>

<gadget id="calculator">6 / 1.5</gadget>
<output>4</output>

<result>4</result>