A and B are walking towards each other at the same time from AB, which is 1200 meters apart. A travels 70 meters per minute, and B travels 50 meters per minute. After they met, they continued to move forward, each arrived at the starting point of the other party and immediately returned along the original road. On the way, the two met for the second time. How many minutes passed from the departure to the second meeting?
甲乙两人同时从相距1200米的AB两地相向而行，甲每分钟行70米，乙每分钟行50米．相遇后又继续前行，各到达对方出发地后立即沿原路返回，途中两人第二次相遇，从出发到第二次相遇经过多少分钟？
<gadget id="calculator">70 + 50</gadget>
<output>120</output>

<gadget id="calculator">3 / 120</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">1_200 * (1/40)</gadget>
<output>30</output>

<result>30</result>