The price of a fountain pen is 2 yuan, which is 3 yuan cheaper than a writing brush. The price of a fountain pen is twice the price of a writing brush. How much is the price of a fountain pen?
一支水芯笔的价钱是2元，比一支毛笔便宜3元，一支钢笔的价钱是毛笔价钱的2倍，一支钢笔的价钱是多少元？
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<result>10</result>