The teacher gave Wang Ming and Liu Qiang some money to buy prizes. Wang Ming said: "You can buy 10 fountain pens with this money." Liu Qiang said: "You can buy 15 ballpoint pens with this money." If you use this money to buy the same number of fountain pens and ballpoint pens, how many of each can you buy?
老师给王明和刘强一些钱去买奖品．王明说："这些钱买钢笔可以买10枝．"刘强说："这些钱买圆珠笔可以买15枝．"如果用这些钱买同样多的钢笔和圆珠笔，可以各买几枝？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) + (1/15)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / (1/6)</gadget>
<output>6</output>

<result>6</result>