A and B cooperate to complete a job in 20 days. Now after A and B cooperate for 5 days, the rest will be completed by B alone in 18 days. Find the work efficiency of B.
一项工作甲、乙合作20天完成，现在甲、乙合作5天后，剩下的由乙独做18天完成，求乙的工作效率．
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) * 5</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) / 18</gadget>
<output>1/24 = around 0.041667</output>

<result>1/24 = around 0.041667</result>