A van and a pickup truck depart from places A and B in the same direction at the same time. The pickup truck is in front and travels 30 kilometers per hour, and the van is behind and travels 70 kilometers per hour. After 3 hours, the van catches up with the pickup truck, how many kilometers is the distance between A and B?
一辆面包车和一辆小货车同时分别从甲乙两地同向出发，小货车在前，每小时行30千米，面包车在后，每小时行70千米．经过3小时面包车追上小货车，甲乙两地路程是多少千米．
<gadget id="calculator">70 - 30</gadget>
<output>40</output>

<gadget id="calculator">40 * 3</gadget>
<output>120</output>

<result>120</result>