A and B start from A and B respectively at the same time and walk toward each other. The first head-on encounter is at a distance of 100 meters from B. After the encounter, A’s speed increases to twice the original speed: A turns around immediately after arriving at B, and when he catches up with B, B still has 50 meters to reach A. Then A and B How many meters is the distance between them?
甲、乙两人分别从A、B两地同时出发，相向而行．第一次迎面相遇在距离B地100米处，相遇后甲的速度提高到原来的2倍：甲到B后立即调头，追上乙时，乙还有50米才到A，那么A、B间的路程长多少米？
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) + 1</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">100 * (5/2)</gadget>
<output>250</output>

<result>250</result>