A truck delivered goods from A to B, and it took 5 hours to go there. When it came back, the speed was increased to 90 kilometers per hour. As a result, it returned to A from the original road in 3.5 hours. How many kilometers per hour does this truck travel when delivering goods to B?
一辆货车从甲地到乙地送货，去时一共用了5小时，回来时速度提高到每小时90千米，结果3.5小时就从原路返回到甲地．这辆货车去乙地送货时每小时行多少千米？
<gadget id="calculator">3.5 / 5</gadget>
<output>0.7</output>

<gadget id="calculator">90 * 0.7</gadget>
<output>63</output>

<result>63</result>