Two small boats kept a distance of 600 meters from the upper reaches of the river. A and B stand at the same place on the river bank. When the boat in front of them comes in front of them, they walk along the river bank with their backs at the same speed at the same time. After A went up for 2 minutes, he met the boat behind him; after B went down for 5 minutes, he was caught up by the boat behind him. Ask the speed of the two people in meters per minute.
两条小船保持600米的间隔从河的上游开下来．甲、乙两人站在河岸的同一地点，当前面的小船来到两人面前时，两人同时以同速沿河岸背向而行．甲向上行2分钟后，遇到后面的小船；乙向下行5分钟后，被后面的小船赶上．问两人的速度是每分钟走多少米．
<gadget id="calculator">600 / 2</gadget>
<output>300</output>

<gadget id="calculator">600 / 5</gadget>
<output>120</output>

<gadget id="calculator">300 - 120</gadget>
<output>180</output>

<gadget id="calculator">180 / 2</gadget>
<output>90</output>

<result>90</result>