It takes 20 days for 30 people to complete a task. If it is completed 5 days ahead of schedule, how many more people are needed?
一项任务30人做需要20天，若提前5天完成，则需要增加多少人？
<gadget id="calculator">30 * 5</gadget>
<output>150</output>

<gadget id="calculator">30 * 20</gadget>
<output>600</output>

<gadget id="calculator">600 - 600</gadget>
<output>0</output>

<gadget id="calculator">150 + 0</gadget>
<output>150</output>

<gadget id="calculator">20 - 5</gadget>
<output>15</output>

<gadget id="calculator">150 / 15</gadget>
<output>10</output>

<result>10</result>