A project can be completed in 24 days by A alone. Now B will do it in 3 days first, and A will need 15 days to do the rest. How many days will B need to do it alone?
一项工程，甲独做24天完成，现在由乙先做3天，余下让甲做还需要15天，乙独做需要多少天．
<gadget id="calculator">1 / 24</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">(1/24) * 15</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 - (5/8)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">3 / (3/8)</gadget>
<output>8</output>

<result>8</result>