It took Xiao Ming 10 hours to go to Shanghai by car from Qingdao, traveling 72 kilometers per hour. Xiaoming took the train when he returned, and it only took 8 hours. What is the speed of the train?
小明从青岛坐车去上海，用了10个小时，每小时行72千米．返回时小明坐火车，只用了8个小时，火车的速度是多少？
<gadget id="calculator">10 / 8</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">72 * (5/4)</gadget>
<output>90</output>

<result>90</result>