Xiaodong and Xiaoqiang start from places A and B at the same time and walk toward each other. Xiaodong travels 120 meters per minute, and Xiaoqiang's speed is twice that of Xiaodong. It is known that the distance between A and B is 720 meters, how many minutes did they walk when they met?
小东和小强两人同时从甲、乙两地出发相向而行，小东每分钟行120米，小强的速度是小东的2倍．已知甲、乙两地的距离是720米，求两人相遇时各走了多少分钟？
<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">720 * (1/3)</gadget>
<output>240</output>

<gadget id="calculator">240 / 120</gadget>
<output>2</output>

<result>2</result>