A person wants to go to a farm 60 kilometers away. He starts to walk at a speed of 5 kilometers per hour. Later, a tractor with a speed of 18 kilometers per hour takes him to the farm. It takes a total of 5.5 hours. Ask: Does he How far did you walk?
某人要到60千米外的农场去，开始以5千米/时的速度步行，后来有辆速度为18千米/时的拖拉机把他送到农场，总共用了5.5小时，问：他步行了多远？
<gadget id="calculator">99 - 60</gadget>
<output>39</output>

<gadget id="calculator">39 / 13</gadget>
<output>3</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<result>15</result>