A project was originally planned to be done by 40 people and completed in 15 days. Now, if it is to be completed 3 days ahead of schedule, how many people need to be added (use a ratio to answer)
一件工程原计划40人做，15天完成，现在要想提前3天完成，还需增加多少人(用比例解答)
<gadget id="calculator">40 * 3</gadget>
<output>120</output>

<gadget id="calculator">15 * 40</gadget>
<output>600</output>

<gadget id="calculator">40 * 15</gadget>
<output>600</output>

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

<gadget id="calculator">120 + 0</gadget>
<output>120</output>

<gadget id="calculator">15 - 3</gadget>
<output>12</output>

<gadget id="calculator">120 / 12</gadget>
<output>10</output>

<result>10</result>