A batch of pineapples are shipped from the fruit wholesale market. The sales in the first week are (17/20) tons, and the sales in the second week are less than (1/5) tons in the first week. How many tons of pineapples are sold in two weeks?
水果批发市场运来一批菠萝，第一周卖出(17/20)吨，第二周卖出的比第一周少(1/5)吨，两周一共卖出菠萝多少吨？
<gadget id="calculator">17 / 20</gadget>
<output>17/20 = around 0.85</output>

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

<gadget id="calculator">(17/20) - (1/5)</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">(13/20) + (17/20)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>