A sailboat travels 6 kilometers per hour, and it takes 15 hours to travel from point A to point B. If you change to a small steamboat, you can save 9 hours. How many kilometers per hour does the small steamboat travel?
一只帆船每小时行6千米，从甲地到乙地用了15小时，如果改乘小汽船，可以少用9小时，小汽船每小时行多少千米？
<gadget id="calculator">15 - 9</gadget>
<output>6</output>

<gadget id="calculator">15 / 6</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">6 * (5/2)</gadget>
<output>15</output>

<result>15</result>