The distance between A and B is 300 kilometers. A large truck and a bus leave from A and B at the same time. After 4 hours, the two vehicles meet. It is known that a large truck travels 35 kilometers per hour, how many kilometers per hour does the bus travel?
甲、乙两地相距300千米，大货车和客车同时从甲、乙两地相对开出，4小时后两车相遇．已知大货车每小时行35千米，求客车每小时行多少千米？
<gadget id="calculator">300 / 4</gadget>
<output>75</output>

<gadget id="calculator">75 - 35</gadget>
<output>40</output>

<result>40</result>