Xiao Liang and Xiao Gang have a total of 30.80 yuan. After they each buy the same pen, Xiao Liang has 5.60 yuan left, and Xiao Gang has 3.20 yuan left. How much is such a pen?
小亮和小刚共有30.80元，两人各买一支同样的钢笔后，小亮还剩5.60元，小刚还剩3.20元，一支这样的钢笔多少钱？
<gadget id="calculator">30.8 - 5.6 - 3.2</gadget>
<output>22</output>

<gadget id="calculator">22 / 2</gadget>
<output>11</output>

<result>11</result>