The telecommunications company wants to lay a communication optical cable. It is planned to be completed by 20 people in 12 days. Due to the urgency of the task, the task must be completed 2 days in advance. If the work efficiency remains the same, how many more people should be added to complete it on time? (answer with ratio)
电讯公司要铺设一条通讯光缆线，计划由20人12天完成，因任务紧急，必须提前2天完成任务，如果工效不变，应增加多少人才能按时完成？(用比例解答)
<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<gadget id="calculator">20 * 12</gadget>
<output>240</output>

<gadget id="calculator">240 - 240</gadget>
<output>0</output>

<gadget id="calculator">40 + 0</gadget>
<output>40</output>

<gadget id="calculator">12 - 2</gadget>
<output>10</output>

<gadget id="calculator">40 / 10</gadget>
<output>4</output>

<result>4</result>