The distance from Panyu Lianhua Port to Hong Kong China Hong Kong City Wharf is 60 nautical miles. A passenger ship travels at a speed of 30 nautical miles per hour. When returning along the original road, the speed is 20 nautical miles per hour due to strong winds. How much longer did it take to return than to go? (Note: A nautical mile is a unit for measuring distance in navigation.)
从番禺莲花港到香港中港城码头的路程为60海里，一艘客轮去时的速度是30海里/时，沿原路返回时，由于刮起了大风，速度是20海里/时．返回时比去时多用了多少时间？(说明：海里是航海上度量距离的单位．)
<gadget id="calculator">60 / 20</gadget>
<output>3</output>

<gadget id="calculator">60 / 30</gadget>
<output>2</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<result>1</result>