A batch of parts can be completed in 6 days by A alone, and 8 days by B alone. Now A alone processes for a few days, and then B alone completes the remaining tasks. In this way, it takes 7 days before and after. How much does A do first? sky.
一批零件，甲单独加工6天可以完成，乙单独加工8天可以完成，现在先由甲单独加工若干天后，再由乙单独完成余下的任务，这样前后共用了7天，甲先做了多少天．
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/8) * 7</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">1 - (7/8)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/6) - (1/8)</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">(1/8) / (1/24)</gadget>
<output>3</output>

<result>3</result>