Two people, A and B, set off from AB at the same time, each branch of A is 80 meters, and each branch of B is 60 meters. They meet at C on the way. If A departs 7 minutes late, the two meet at D on the way. And the distance between C and D is equal to the midpoint, how many meters are AB and AB?
甲乙两人同时从AB两地出发，甲每分行80米，乙每分行60米，两人在途中C地相遇．若甲晚出发7分，两人在途中D地相遇．且C、D两地距中点相等，AB两地多少米？
<gadget id="calculator">80 + 60</gadget>
<output>140</output>

<gadget id="calculator">80 - 60</gadget>
<output>20</output>

<gadget id="calculator">7 / 20</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">80 * (7/20)</gadget>
<output>28</output>

<gadget id="calculator">140 * 28</gadget>
<output>3_920</output>

<result>3_920</result>