Cars A and B travel opposite each other from A and B at the same time. When A arrives at B, B is 30 kilometers away from A. When B arrives at A, A passes 40 kilometers away from B. How many kilometers are there between A and B?
甲、乙两车同时从A、B两地相向二行，当甲车到达B地时，乙车距离A地30千米，当乙车到达A地时，甲车超过B地40千米，A、B地相距多少千米？
<gadget id="calculator">40 / 30</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">(4/3) * 30</gadget>
<output>40</output>

<gadget id="calculator">(4/3) - 1</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">40 / (1/3)</gadget>
<output>120</output>

<result>120</result>