and B run back and forth on a straight road 100 meters apart. A runs 2.8 meters per second and B runs 2.2 meters per second. They started at both ends of the straight road at the same time. When they ran for 30 minutes, how many times did they meet during this period?
甲、乙二人相距100米的直路上来回跑步，甲每秒钟跑2.8米，乙每秒钟跑2.2米．他们同时分别在直路两端出发，当他们跑了30分钟时，这段时间内相遇了多少次．
<gadget id="calculator">44 + 1</gadget>
<output>45</output>

<result>45</result>