The railway from Tianjin to Jinan is 357 kilometers long. An express train departs from Tianjin, and a slow train departs from Jinan at the same time. The two trains run towards each other and meet after 3 hours. The express train travels an average of 79 kilometers per hour, how many kilometers per hour does the slow train travel on average?
天津到济南的铁路长357千米，一列快车从天津开出，同时一辆慢车从济南开出，两车相向而行，经过3小时相遇．快车平均每小时行79千米，慢车平均每小时行多少千米？
<gadget id="calculator">357 / 3</gadget>
<output>119</output>

<gadget id="calculator">119 - 79</gadget>
<output>40</output>

<result>40</result>