A project is completed in 20 days by A alone, 40 days by B alone, and after 5 days of cooperation between A and B, the rest will be completed by B. How many days will B need to complete?
一项工程，甲单独做20天完成，乙单独做40天完成，甲、乙合作5天后，剩下的由乙完成，乙还需要几天才能完成？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 40</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">(1/20) + (1/40)</gadget>
<output>3/40 = around 0.075</output>

<gadget id="calculator">(3/40) * 5</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">1 - (3/8)</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">(5/8) / (1/40)</gadget>
<output>25</output>

<result>25</result>