Two passenger trains A and B depart from two places 680 kilometers apart at the same time. A travels 42 kilometers per hour and meets each other in 8 hours. How many kilometers per hour does B passenger train travel?
甲乙两列客车同时由相距680千米的两地同时相对出发，甲每小时行42千米，8小时相遇，乙客车每小时行多少千米．
<gadget id="calculator">680 / 8</gadget>
<output>85</output>

<gadget id="calculator">85 - 42</gadget>
<output>43</output>

<result>43</result>