Each loom in a textile factory weaves (21/5) meters per hour, and 3 looms need to weave 84 meters. How many hours will it take?
纺织厂每台织布机每小时织布(21/5)米，3台织布机要织布84米，需要多少小时？
<gadget id="calculator">21 / 5</gadget>
<output>21/5 = around 4.2</output>

<gadget id="calculator">84 / 3 / (21/5)</gadget>
<output>20/3 = around 6.666667</output>

<result>20/3 = around 6.666667</result>