A car drives from place A to place B. It originally planned to drive 40 kilometers per hour, but actually traveled 10 kilometers per hour, so it arrived at place B 2 hours earlier than the original plan. How many kilometers are there between A and B?
汽车从甲地开往乙地，原计划每小时行40千米，实际每小时多行了10千米，这样比原计划提前2小时到达了乙地．甲、乙两地相距多少千米？
<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">80 + 20</gadget>
<output>100</output>

<gadget id="calculator">10 - 40</gadget>
<output>-30</output>

<gadget id="calculator">40 + (-30)</gadget>
<output>10</output>

<gadget id="calculator">100 / 10</gadget>
<output>10</output>

<gadget id="calculator">10 * 40</gadget>
<output>400</output>

<result>400</result>