The passenger car and the freight car start from A and B, which are 560 kilometers apart, and drive towards each other. After 4 hours, the two cars meet on the way. Given that the speed of the passenger car is 80 km/h, find the speed of the truck.
客车和货车同时从相距560千米的A、B两地出发，相向而行，4小时后两车在途中相遇．已知客车速度是80千米/时，求货车的速度．
<gadget id="calculator">560 / 4</gadget>
<output>140</output>

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

<result>60</result>