A car travels from A to B at a speed of 63 kilometers per hour, takes 4 hours, and only takes 3 hours to return. How many kilometers per hour does the car drive and return?
一辆汽车从甲地开往乙地，去时的速度是每小时63千米，共用4小时，返回时只用了3小时，这辆汽车开往和返回总平均每小时行多少千米？
<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">63 * 4 * (2/7)</gadget>
<output>72</output>

<result>72</result>