The bookstore shipped a batch of new books, sold (1/4) of the total in the first week, and sold (2/5) of the total in the second week, exactly 1300 copies were sold in two weeks, how many new books are there in this batch?
书店运来一批新书，第一周卖出了总数的(1/4)，第二周卖出了总数的(2/5)，两周正好卖出1300本，这批新书有多少本？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">(1/4) + (2/5)</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">1_300 / (13/20)</gadget>
<output>2_000</output>

<result>2_000</result>