The captain found that the boat was leaking, some water had already entered, and the water was still entering the boat at a constant speed, so he needed to arrange personnel to drain water immediately. If 8 people drain the water, it takes 5 hours to finish it; if 12 people drain it, it takes 3 hours to finish it. Now it takes 2 hours to finish, how many people need to be arranged.
船长发现船正在漏水，已经进了一些水，水还在匀速地进入船内，需要立即安排人员排水．若8人排水，5小时排完；如果12人排水，3小时排完．现在要2小时排完，需要安排多少人．
<gadget id="calculator">8 * 5</gadget>
<output>40</output>

<gadget id="calculator">12 * 3</gadget>
<output>36</output>

<gadget id="calculator">40 - 36</gadget>
<output>4</output>

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

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

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

<gadget id="calculator">40 - 10</gadget>
<output>30</output>

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

<gadget id="calculator">30 + 4</gadget>
<output>34</output>

<gadget id="calculator">34 / 2</gadget>
<output>17</output>

<result>17</result>