Xiao Ming bought 2 pencils and 2 pens, and shared 20 yuan. It is known that each pencil is 1.5 yuan, so how much is each pen? (solution by equation)
小明买来铅笔和钢笔各2支，共用了20元，已知每支铅笔1.5元，那么每支钢笔多少元？(用方程解)
<gadget id="calculator">1.5 * 2</gadget>
<output>3</output>

<gadget id="calculator">20 - 3</gadget>
<output>17</output>

<gadget id="calculator">17 / 2</gadget>
<output>17/2 = around 8.5</output>

<result>17/2 = around 8.5</result>