800 parts are processed, and (3/5) of them are processed in 3 hours. How many hours will the rest be processed in this way?
加工800个零件，3小时加工它的(3/5)，照这样余下的还要加工多少小时．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(3/5) / 3</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(2/5) / (1/5)</gadget>
<output>2</output>

<result>2</result>