The length of the railway between A and B is 1760 km. At 8 o'clock in the morning, an express train and a slow train depart from the two places at the same time and run toward each other. At 5 o'clock in the afternoon, the distance between the two cars is 320 kilometers. It is known that the fast train travels 85 kilometers per hour, how many kilometers per hour does the slow train travel?
甲乙两地的铁路长1760千米．上午8点快车和一列慢车同时从两地出发相向而行，下午5点，两车还相距320千米．已知快车每小时行85千米，慢车每小时行多少千米？
<gadget id="calculator">1_760 - 320</gadget>
<output>1_440</output>

<gadget id="calculator">1_440 / 9</gadget>
<output>160</output>

<gadget id="calculator">160 - 85</gadget>
<output>75</output>

<result>75</result>