A butterfly flies 46.8 kilometers in 1.5 hours, and a bee flies 19.5 kilometers per hour. How much less miles per hour do bees fly than butterflies?
一只蝴蝶1.5小时飞行46.8千米，一只蜜蜂每小时飞行19.5千米．蜜蜂比蝴蝶每小时少飞行多少千米？
<gadget id="calculator">46.8 / 1.5</gadget>
<output>31.2</output>

<gadget id="calculator">31.2 - 19.5</gadget>
<output>11.7</output>

<result>11.7</result>