To process a pile of rice, A thresher alone can complete it in 8 hours, and B thresher alone can complete it in 6 hours. If A thresher does it for 1 hour first, then two threshers A and B cooperate to do it. How many hours to finish?
加工一堆稻谷，甲脱粒机单独做8小时完成，乙脱粒机单独做6小时完成．如果甲脱粒机先做1小时，再由甲乙两部脱粒机合做．还要几小时完成？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

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

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

<gadget id="calculator">(1/8) + (1/6)</gadget>
<output>7/24 = around 0.291667</output>

<gadget id="calculator">(7/8) / (7/24)</gadget>
<output>3</output>

<result>3</result>