Two vehicles, A and B, start from A and B at the same time, and drive back and forth between A and B without interruption. It is known that the speed of A and B is 15km/h, and the speed of B is 25km/h. The difference between the third meeting point and the fourth meeting point of two cars B is 100km, how many kilometers are the distance between A and B?
甲、乙两车分别从A、B两地同时出发，并在A、B两地不间断地往返行驶，已知甲车的速度是15km/h，乙车的速度是25km/h，甲、乙两车第三次相遇点与第四次相遇点相差100km，A、B两地相距多少千米？
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">15 - 10</gadget>
<output>5</output>

<gadget id="calculator">9 - 5</gadget>
<output>4</output>

<gadget id="calculator">100 / 4</gadget>
<output>25</output>

<gadget id="calculator">25 * 10</gadget>
<output>250</output>

<result>250</result>