Two masters and apprentices process a batch of parts, and 1/3 of the total number has been processed after 2 days. If all the parts are processed by the master alone, it will take 10 days to complete. If all the parts are processed by the apprentice, how many days will it take to complete?
师徒两人加工一批零件，2天后已加工总数的(1/3)，这批零件如果全部由师傅单独加工，需10天完成，如果全部由徒弟加工需几天完成？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/3) / 2</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/6) - (1/10)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / (1/15)</gadget>
<output>15</output>

<result>15</result>