It takes 20 days for A to do a job alone, and 34 days for B to do it alone. If two people cooperate, the work efficiency will be reduced. A’s work efficiency will be reduced by 20%, and B’s work efficiency will be reduced by 15%. Now it takes 17 days to complete this job. For work, the number of days of cooperation between the two should be as small as possible, and the minimum number of days should be the minimum number of days for the two to cooperate.
一项工作，甲单独做要20天，乙单独做要34天，如果两人合作，工作效率就要降低，甲的工效降低20%，乙的工效降低15%，现在要17天完成这项工作，两人合作天数尽量少，两人最少合作多少天．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(4/5) * (1/20)</gadget>
<output>1/25 = around 0.04</output>

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

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

<gadget id="calculator">17 * (1/25)</gadget>
<output>17/25 = around 0.68</output>

<gadget id="calculator">1 - (17/25)</gadget>
<output>8/25 = around 0.32</output>

<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1 - (3/20)</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">1 / 34</gadget>
<output>1/34 = around 0.029412</output>

<gadget id="calculator">(17/20) * (1/34)</gadget>
<output>1/40 = around 0.025</output>

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

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

<gadget id="calculator">(1/40) - (1/25)</gadget>
<output>-3/200 = around -0.015</output>

<gadget id="calculator">(1/25) + (-3/200)</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">(8/25) / (1/40)</gadget>
<output>64/5 = around 12.8</output>

<result>64/5 = around 12.8</result>