A and B practice running along a 400-meter circular track, and they run from the same point on the track in opposite directions at the same time. After meeting, A increases by 2 m/s compared to the original speed, B decreases by 2 m/s compared to the original speed, and it takes 25 seconds for both of them to return to the original place at the same time. Find the original speed of A.
甲，乙两人沿400米环行跑道练习跑步，两人同时从跑道的同一地点相反方向跑去．相遇后甲比原来速度增加2米/秒，乙比原来速度减少2米/秒，结果都用25s同时回到原地．求甲原来的速度．
<gadget id="calculator">400 / 25</gadget>
<output>16</output>

<gadget id="calculator">16 - 2</gadget>
<output>14</output>

<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<result>7</result>