When a typist types a manuscript, A can finish typing in 4 hours alone, B can finish typing in 8 hours alone, and after two hours of typing together, the rest can be typed by B alone. How many hours will it take?
打字员打一部稿件，甲单独打4小时可打完，乙单独打8小时打完，二人合打2小时后，剩下的由乙独打，还需要几小时打完？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/4) + (1/8)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(3/8) * 2</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) / (1/8)</gadget>
<output>2</output>

<result>2</result>