Cars A and B leave opposite directions at the same time, and the two cars meet after 4.5 hours. It is known that the distance between the two places is 387 kilometers. If car A travels 42 kilometers per hour, how many kilometers will car B travel per hour?
甲、乙两车同时从两地相向开出，4.5小时后两车相遇．已知两地相距387千米，甲车每小时行42千米，乙车每小时行多少千米？
<gadget id="calculator">387 / 4.5</gadget>
<output>86</output>

<gadget id="calculator">86 - 42</gadget>
<output>44</output>

<result>44</result>