The library bought 240 science and technology books, which is 40% less than the literary books bought. How many literary books were bought? (solution by equation)
图书室买来240本科技书，比买来的文艺书少40%，买来文艺书多少本？(用方程解)
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">240 / (3/5)</gadget>
<output>400</output>

<result>400</result>