Car A and car B drove from Yangzhou to Nanjing at the same time. After 4 hours, car A fell behind car B 28 kilometers away. Car A travels 68 kilometers per hour, how many kilometers per hour does Car B travel?
甲、乙两辆汽车同时从扬州开往南京，经过4小时后，甲车落在乙车后面28千米．甲车每小时行68千米，乙车每小时行多少千米？
<gadget id="calculator">28 / 4</gadget>
<output>7</output>

<gadget id="calculator">7 + 68</gadget>
<output>75</output>

<result>75</result>