The distance between A and B is 180km. An express train and a slow train depart from the two stations at the same time and meet each other after 1.5 hours. The speed of the express train is 1.5 times that of the slow train. How many hours will it take for the express train to complete the journey?
甲乙两地相距180km，一列快车和一列慢车分别从两站同时相向开出，1.5时后相遇，快车的速度是慢车的1.5倍，快车行完全程要多少小时？
<gadget id="calculator">180 / 1.5</gadget>
<output>120</output>

<gadget id="calculator">120 / 2.5</gadget>
<output>48</output>

<gadget id="calculator">48 * 1.5</gadget>
<output>72</output>

<gadget id="calculator">180 / 72</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>