Teacher Li bought 16 bottles of ink and 18 pens, and paid a total of 350 yuan. Each bottle of ink is 5 yuan. How much is each pen?
李老师购买了16瓶墨水和18只钢笔，共付了350元，每瓶墨水5元，每只钢笔多少元？
<gadget id="calculator">16 * 5</gadget>
<output>80</output>

<gadget id="calculator">350 - 80</gadget>
<output>270</output>

<gadget id="calculator">270 / 18</gadget>
<output>15</output>

<result>15</result>