It takes 4 hours for a boat to travel downstream from A to B, and 6 hours to travel upstream from B to A. How many hours does it take for a raft to travel from A to B?
一轮船从甲地到乙地顺水行驶需要4小时，从乙地到甲地逆水行驶需要6小时，有一木筏由甲地漂流到乙地需要多少小时．
<gadget id="calculator">1 / 24</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">1 / (1/24)</gadget>
<output>24</output>

<result>24</result>