A project can be completed in 40 days by team A alone, and completed by team B in 30 days alone. Now team A will do it in 5 days first, and the rest will be done by teams A and B. How many days will it take to finish?
一项工程，甲队独做40天写成，乙队独做30天完成，现在甲队先做5天，余下的由甲乙两队合做．还需几天完成？
<gadget id="calculator">1 / 40</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">(1/40) * 5</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 - (1/8)</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/40) + (1/30)</gadget>
<output>7/120 = around 0.058333</output>

<gadget id="calculator">(7/8) / (7/120)</gadget>
<output>15</output>

<result>15</result>