The distance between A and B is 560 kilometers. Now two passenger and freight vehicles leave from A and B at the same time. The trucks travel 60 kilometers per hour and meet each other after 4 hours. Find the speed of the bus.
甲、乙两地相距560千米，现在客货两车同时从甲、乙两地相对开出，货车每小时行驶60千米，经过4小时相遇．求客车的速度．
<gadget id="calculator">560 / 4</gadget>
<output>140</output>

<gadget id="calculator">140 - 60</gadget>
<output>80</output>

<result>80</result>