A project can be completed by A alone in 16 days, and by B alone in 12 days. Now B will do the work for 3 days first, and A will do the rest. How many days will it take to complete the project?
一项工程，甲单独做16天可以完成，乙单独做12天可以完成．现在由乙先做3天，剩下的由甲来做，还需要多少天能完成这项工程？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/12) * 3</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 16</gadget>
<output>1/16 = around 0.0625</output>

<gadget id="calculator">(3/4) / (1/16)</gadget>
<output>12</output>

<result>12</result>