A steel pipe, after cutting off (2/5) of its full length, there are 30 meters left. What is the length of this steel pipe?
一根钢管，截去全长的(2/5)后，还剩30米．这根钢管全长是多少米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">30 / (3/5)</gadget>
<output>50</output>

<result>50</result>