After the sixth speed increase, the distance between Beijing and Shanghai is 1200km. Two direct express trains depart from Beijing and Shanghai at the same time. The speed of the two trains is the same. After 6 hours, the two trains meet. What is their speed?
第六次大提速以后，北京和上海相距1200km，两列直快火车同时从北京和上海相对开出，两车的速度相同，6小时后两车相遇，它们的速度是多少？
<gadget id="calculator">1_200 / 6 / 2</gadget>
<output>100</output>

<result>100</result>