A ship hit a rock and broke a hole. The sea water evenly entered the ship. When the leak was discovered, the ship had already entered some water. If 12 people scoop the water, the water can be scooped out in 3 hours; if 5 people scoop the water, the water can be scooped in 10 hours. How many people are needed if the water needs to be scooped up within 2 hours.
有一条船因触礁，破了一个洞，海水均匀地进入船内，发现船漏时，船已进了一些水．如果12个人舀水，则3个小时可以把水舀完；如果5人舀水，则10小时可以把水舀完．如果需要在2小时内舀完水，则需要多少人．
<gadget id="calculator">5 * 10</gadget>
<output>50</output>

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

<gadget id="calculator">50 - 36</gadget>
<output>14</output>

<gadget id="calculator">10 - 3</gadget>
<output>7</output>

<gadget id="calculator">14 / 7</gadget>
<output>2</output>

<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">50 - 20</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>