Ship A and the self-drifting water flow tester sail from the upstream station A to the downstream station B at the same time, and at the same time, the ship B starts from station B and sails upstream to station A. After 7.2 o'clock, the second ship meets the self-drifting current tester. It is known that ship A is 31.25 kilometers away from the self-drifting current tester after 2.5 hours, and the speed of ship A and ship B is equal. Find the distance between stations A and B.
甲轮船和自漂水流测试仪同时从上游的A站顺水向下游的B站驶去，与此同时乙轮船自B站出发逆水向A站驶来．7.2时后乙轮船与自漂水流测试仪相遇．已知甲轮船与自漂水流测试仪2.5时后相距31.25千米，甲、乙两船航速相等，求A，B两站的距离．
<gadget id="calculator">31.25 / 2.5</gadget>
<output>12.5</output>

<gadget id="calculator">12.5 * 7.2</gadget>
<output>90</output>

<result>90</result>