A and B are walking toward each other from A and B at the same time. A travels 20 kilometers in 5 hours. At this time, he meets B. After meeting, B travels for another 4 hours to reach A. How many kilometers are there between A and B?
甲、乙两人同时从A、B两地相向而行，甲5小时行20千米，此时正好和乙相遇，相遇后乙又行了4小时到达A地．A、B两地相距多少千米？
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">25 + 20</gadget>
<output>45</output>

<result>45</result>