Two cars drive from A and B oppositely at the same time. A travels 40 kilometers per hour, and B travels 50 kilometers per hour. After 5 hours, they have traveled half of the journey. How many kilometers are there between A and B? ?
两辆汽车分别同时从甲、乙两地相对开出，甲每小时行40千米，乙每小时行50千米，经过5小时共行了全程的一半，甲、乙两地相距多少千米？
<gadget id="calculator">40 + 50</gadget>
<output>90</output>

<gadget id="calculator">90 * 5 * 2</gadget>
<output>900</output>

<result>900</result>