Two people, A and B, are walking toward each other from two places 360 kilometers apart at the same time, and they meet after 7.2 hours. The speed of A is three times that of B. How many kilometers does B travel per hour?
甲、乙二人同时从相距360千米的两地相向而行，7.2小时后相遇，甲的速度是乙的3倍，乙每小时行多少千米？
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">360 / 7.2 / 4</gadget>
<output>12.5</output>

<result>12.5</result>