The Drought Relief Headquarters transports a batch of relief supplies from A to B, travels 50 kilometers per hour, and arrives at B in 3 hours. Since there is a new task, it is required to arrive in 2.5 hours when returning. How many kilometers per hour? (requires an equation solution)
抗旱指挥部从甲地运送一批救灾物资到乙地，去时每小时行50千米，3小时到达乙地．由于又有新的任务，返回时要求2.5小时必须赶到，每小时行几千米？(要求用方程解答)
<gadget id="calculator">50 * 3</gadget>
<output>150</output>

<gadget id="calculator">150 / 2.5</gadget>
<output>60</output>

<result>60</result>