For a batch of typing tasks, A can finish typing in 20 hours, B can finish typing in 25 hours, the two can work together for 5 hours, and the rest can be done by B. How many hours does B need to finish typing?
一批打字任务，甲20小时可打完，乙25小时可打完，两人合打5小时，剩下的由乙打，乙还要多少小时可打完？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 25</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">(1/20) + (1/25)</gadget>
<output>9/100 = around 0.09</output>

<gadget id="calculator">(9/100) * 5</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 - (9/20)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">(11/20) / (1/25)</gadget>
<output>55/4 = around 13.75</output>

<result>55/4 = around 13.75</result>