An engineering team repaired a canal, and built (3/5) kilometers on the first day, which was (1/5) kilometers less than the second day, and it was exactly the full length (2/5) in two days. What is the length of the canal?
某工程队修一条水渠，第一天修了(3/5)千米，比第二天少修(1/5)千米，两天修的正好是全长的(2/5)，这条水渠长是多少？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(3/5) + (1/5) + (3/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(7/5) / (2/5)</gadget>
<output>7/2 = around 3.5</output>

<result>7/2 = around 3.5</result>