A project can be completed by A alone in 8 days and B by himself in 10 days. Now A will do it alone for 3 days, and then A and B will work together for the rest. How many days will it take to complete?
一项工程，甲独做8天完成，乙独做10天完成．现在由甲先独做3天，余下的甲、乙合做，还需多少天完成？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/8) * 3</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">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/8) + (1/10)</gadget>
<output>9/40 = around 0.225</output>

<gadget id="calculator">(5/8) / (9/40)</gadget>
<output>25/9 = around 2.777778</output>

<result>25/9 = around 2.777778</result>