Xiaohong bought 3 fountain pens and 2 ballpoint pens, and they shared 19 yuan; Xiaodong bought 2 fountain pens and 3 ballpoint pens, and shared 16 yuan; how much would it cost to buy a fountain pen and a ballpoint pen?
小红买了3支钢笔和2支圆珠笔，共用去19元；小东买了2支钢笔和3支圆珠笔，共用去16元；若买一支钢笔和一支圆珠笔共需要多少元．
<gadget id="calculator">16 * 3</gadget>
<output>48</output>

<gadget id="calculator">19 * 2</gadget>
<output>38</output>

<gadget id="calculator">48 - 38</gadget>
<output>10</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">9 - 4</gadget>
<output>5</output>

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

<gadget id="calculator">19 - 4</gadget>
<output>15</output>

<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<gadget id="calculator">2 + 5</gadget>
<output>7</output>

<result>7</result>