Uncles of the People’s Liberation Army who participated in the earthquake rescue walked into the disaster area on foot. If they walked as usual, they would walk an average of 70 meters per minute. Enter the disaster area a few minutes earlier than walking at a normal speed? If entering 1 minute earlier can give 20 people the chance to regenerate, how many people have they given the chance to regenerate in total?
参加地震救援的解放军叔叔步行进入灾区，若按常规行走，平均每分钟走70米；为了尽快赶到灾区，他们每分钟走90米，结果用42分钟进入指定区域，请你算一算，他们比用常速行走提前几分钟进入灾区？如果以每提早1分钟进入，可以使20人获得再生的机会，他们一共使多少人获得了再生的机会？
<gadget id="calculator">42 / 70</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">90 * (3/5)</gadget>
<output>54</output>

<gadget id="calculator">54 - 42</gadget>
<output>12</output>

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

<result>240</result>