For a manuscript, it takes 20 hours for A to type alone, and 15 hours for B to type alone. If this manuscript is printed by A alone (1/3), and the rest is printed by B, how many hours will B need to finish?
一份稿件，甲单独打需20小时完成，乙单独打需15小时完成．如果这份稿件先由甲单独打印完成(1/3)，剩下的由乙继续打印，乙还需几小时完成？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(2/3) / (1/15)</gadget>
<output>10</output>

<result>10</result>