Two cars drive in opposite directions from two places, and they meet at a distance of 20 kilometers from the midpoint. It is known that car B has traveled the entire distance (2/5), how many kilometers is the total length of this road.
两辆汽车分别从两地相向开出，在距中点20千米处两车相遇，已知乙车行了全程的(2/5)，这条公路全长多少千米．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5) - (2/5)</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">20 * 10</gadget>
<output>200</output>

<result>200</result>