There is a batch of books in a bookstore, which are sold on the first day (3/5), and another batch of books are bought in the second day, the quantity is (1/2) of the books sold on the first day, and the bookstore has 350 books of this kind at this time How many books of this kind does the bookstore have?
某书店有一批图书，第一天售出(3/5)，第二天又进了一批图书，数量是第一天售书的(1/2)，这时书店存有这类图书350本，书店原有这类图书多少本？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(3/5) * (1/2)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(2/5) + (3/10)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">350 / (7/10)</gadget>
<output>500</output>

<result>500</result>