Two trains of urban railways depart from the two cities at the same time. One train travels 40 kilometers per hour, and the other train travels 45 kilometers per hour. On the way, each train stops 4 times for 15 minutes each time. Two cars meet each other in 7 hours, find the distance between the two cities?
两列城铁从两城同时相对开出，一列城铁每小时走40千米，另一列城铁每小时走45千米，在途中每列车先后各停车4次，每次停车15分钟，经过7小时两车相遇，求两城的距离？
<gadget id="calculator">40 + 45</gadget>
<output>85</output>

<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">85 * 6</gadget>
<output>510</output>

<result>510</result>