A passenger car with a length of 120 meters is traveling eastward at a speed of 80 km/h. The 280-meter-long truck is heading west. They meet at the west end of a 130-meter-long railway bridge and leave at the east end of the bridge. What is the speed of the truck in km/h.
长120米的客车，以80千米/小时的速度向东行驶．长280米的货车往西行驶．它们在一座长130米的铁路桥西端相遇，在桥的东端离开．货车的速度是多少千米/小时．
<gadget id="calculator">280 - 130</gadget>
<output>150</output>

<gadget id="calculator">150 / 1_000</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">120 + 130</gadget>
<output>250</output>

<gadget id="calculator">250 / 1_000 / 80</gadget>
<output>1/320 = around 0.003125</output>

<gadget id="calculator">(3/20) / (1/320)</gadget>
<output>48</output>

<result>48</result>