Using 400 tons of wheat to grind flour, the flour extraction rate is 85%. How many tons of flour can be ground?
用400吨小麦磨面粉，出粉率85%．可以磨面粉多少吨？
<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">400 * (17/20)</gadget>
<output>340</output>

<result>340</result>