A project can be completed by team A alone in 10 days and by team B in 15 days. If Team A works for one day first, and then Team B joins in, how many days will it take to complete?
一项工程，由甲队单独做需要10天完成，由乙队单独做需要15天完成．如果甲队先做1天后，乙加入一同做，还要几天才能完成？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) + (1/15)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(9/10) / (1/6)</gadget>
<output>27/5 = around 5.4</output>

<result>27/5 = around 5.4</result>