truck travels 320 km in 4 hours and a bus travels 550 km in 5 hours. How much more miles per hour will the bus travel than the truck?
一辆卡车4小时行驶320千米，一辆客车5小时行驶550千米．这辆客车比这辆卡车每小时多行多少千米．
<gadget id="calculator">550 / 5</gadget>
<output>110</output>

<gadget id="calculator">320 / 4</gadget>
<output>80</output>

<gadget id="calculator">110 - 80</gadget>
<output>30</output>

<result>30</result>