The distance between A and B is 800 kilometers. Two cars A and B start from the two places at the same time and drive toward each other. After 8 hours, they meet each other. It is known that car A travels 45 kilometers per hour, how many kilometers per hour does B travel?
甲、乙两地相距800千米，甲、乙两辆汽车同时从两地出发相向而行，经8小时相遇，已知甲车每小时行45千米，乙车每小时行多少千米？
<gadget id="calculator">800 / 8</gadget>
<output>100</output>

<gadget id="calculator">100 - 45</gadget>
<output>55</output>

<result>55</result>