A road has been repaired for a full length (1/4), and there is still 40 kilometers away from the midpoint. What is the correct formula for the total length of this road?
一条公路修了全长的(1/4)，离中点还有40千米，这条公路的全长的正确算式是多少
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/2) - (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">40 / (1/4)</gadget>
<output>160</output>

<result>160</result>