The distance between A and B is 864 kilometers. Two cars, A and B, drive from the two places respectively. The two cars meet on the way in 6.4 hours. It is known that car B travels 87.5 kilometers per hour. How many kilometers per hour does car A travel? ?
A、B两地相距864千米，甲乙两辆汽车分别从两地相对开出，6.4小时两辆汽车在途中相遇，已知乙车每小时行87.5千米，甲车每小时行多少千米？
<gadget id="calculator">864 / 6.4</gadget>
<output>135</output>

<gadget id="calculator">135 - 87.5</gadget>
<output>47.5</output>

<result>47.5</result>