The engineering team wanted to build a canal. It was originally planned that 50 people would finish the work in 40 days, but it took 25 days to finish it. How many people actually participated in the construction of the canal?
工程队要修一条水渠，原计划50人40天修完，实际用了25天修完，实际参加修水渠的有多少人？
<gadget id="calculator">50 * 40</gadget>
<output>2_000</output>

<gadget id="calculator">1 / 2_000</gadget>
<output>1/2_000 = around 0.0005</output>

<gadget id="calculator">(1/2_000) * 25</gadget>
<output>1/80 = around 0.0125</output>

<gadget id="calculator">1 / (1/80)</gadget>
<output>80</output>

<result>80</result>