If 2.4 meters are cut off from a wire, 40% of the total length remains. If 75% of the total length is to be left, how many meters should be cut off?
一根电线剪去2.4米，还剩下全长的40%，要想剩下全长的75%，应剪去多少米．
<gadget id="calculator">40 / 100</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">2.4 / (3/5)</gadget>
<output>4</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">4 * (1/4)</gadget>
<output>1</output>

<result>1</result>