It costs 23.2 yuan to buy 3 diaries and 2 boxes of colored pens, and 27.8 yuan to buy 2 diaries and 3 boxes of colored pens. How much is a box of colored pens?
买3本日记本和2盒彩笔需要23.2元，买2本日记本和3盒彩笔需要27.8元，一盒彩笔多少元？
<gadget id="calculator">23.2 + 27.8</gadget>
<output>51</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">51 / 5</gadget>
<output>51/5 = around 10.2</output>

<gadget id="calculator">(51/5) * 2</gadget>
<output>102/5 = around 20.4</output>

<gadget id="calculator">27.8 - (102/5)</gadget>
<output>7.4</output>

<result>7.4</result>