After a bundle of cables is cut off (2/5), another 20 meters are used, and the remaining part is exactly 50% of the total length. How many meters is this bundle of cables?
一捆电缆截去(2/5)后，又用去20米，剩下的部分正好是全长的50%，这捆电缆有多少米长？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (2/5) - (1/2)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">20 / (1/10)</gadget>
<output>200</output>

<result>200</result>