A butterfly flies 15.6 kilometers in 2 hours, and a bee flies 2.4 times faster than the butterfly. How many kilometers does this bee fly per hour?
一只蝴蝶2小时飞行15.6千米，一只蜜蜂的飞行速度是蝴蝶的2.4倍．这只蜜蜂每小时飞行多少千米？
<gadget id="calculator">15.6 / 2</gadget>
<output>7.8</output>

<gadget id="calculator">7.8 * 2.4</gadget>
<output>18.72</output>

<result>18.72</result>