The length of the railway between A and B is 660 kilometers. A passenger train travels from A to B, and a freight train travels from B to A. After 4 hours, the two trains meet and the passenger train travels 90 kilometers per hour. How many miles does the truck travel per hour?
甲乙两站之间的铁路长660千米，一列客车从甲站开往乙站，同时有一列货车从乙站开往甲站，经过4小时两列火车相遇，客车每小时行90千米，货车每小时行多少千米？
<gadget id="calculator">90 * 4</gadget>
<output>360</output>

<gadget id="calculator">660 - 360</gadget>
<output>300</output>

<gadget id="calculator">300 / 4</gadget>
<output>75</output>

<result>75</result>