task can be completed by 5 people in Group A in 8 days, and by 10 people in Group B in 4 days. Now send 4 people from Group A and 6 people from Group B to cooperate. How many days can this work be completed?
一项工作，甲组5人8天可以完成，乙组10人4天可以完成．现在派甲组4人和乙组6人合作，多少天可以完成这项工作？
<gadget id="calculator">5 * 8</gadget>
<output>40</output>

<gadget id="calculator">4 / 40</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">4 * 10</gadget>
<output>40</output>

<gadget id="calculator">6 / 40</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(1/10) + (3/20)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / (1/4)</gadget>
<output>4</output>

<result>4</result>