There are two boxes, box A contains black pieces, box B contains white pieces, the ratio of black and white pieces is 3:8, if take out 14 white pieces from box B and replace them with black pieces and put them in box A Here, the ratio of black and white pieces is 2:3. How many black chess pieces were originally contained in box A?
有两个盒子，甲盒子里装有黑棋子，乙盒子里装有白棋子，黑、白棋子的比为3：8，如果从乙盒子里取出14个白棋子换成黑棋子放在甲盒子里，此时黑、白棋子的比为2：3．甲盒子里原来装有黑棋子多少个？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3 / 11</gadget>
<output>3/11 = around 0.272727</output>

<gadget id="calculator">(2/5) - (3/11)</gadget>
<output>7/55 = around 0.127273</output>

<gadget id="calculator">14 / (7/55)</gadget>
<output>110</output>

<gadget id="calculator">110 * (3/11)</gadget>
<output>30</output>

<result>30</result>