From home to the city library, Landy can walk for 0.5h at a speed of 3km per hour. How many hours does it take for him to walk home along the same road at a speed of 2 km per hour?
Landy从家到市图书馆，按每小时3km的速度，步行0.5h可以到达．他沿着原路回家，按每小时2km的速度，需要步行多少小时？
<gadget id="calculator">0.5 / 2</gadget>
<output>0.25</output>

<gadget id="calculator">3 * 0.25</gadget>
<output>0.75</output>

<result>0.75</result>