To speed up the train. The railway workers replaced the original 20-meter-long old rails with new 25-meter-long rails. A total of 180 old rails were replaced. How many new rails were replaced? (Solution with proportional knowledge)
为了火车提速．铁路工人用每根长25米的新铁轨替换原来每根长20米的旧铁轨，共换下旧铁轨180根，换上的新铁轨有多少根？(用比例知识解)
<gadget id="calculator">20 * 180</gadget>
<output>3_600</output>

<gadget id="calculator">3_600 / 25</gadget>
<output>144</output>

<result>144</result>