The distance between AB and AB is 600 meters. Two people, A and B, are walking in the same direction from A and B at the same time, with A in front of B and behind. Each branch of A is 40 meters, B catches up with A after 6 minutes, find the speed of B.
AB两地相距600米，甲乙两人同时分别从A、B两地向同一个方向行走，甲前乙后．甲每分行40米，6分钟后乙追上甲，求乙的速度．
<gadget id="calculator">40 * 6</gadget>
<output>240</output>

<gadget id="calculator">240 + 600</gadget>
<output>840</output>

<gadget id="calculator">840 / 6</gadget>
<output>140</output>

<result>140</result>