In the library of Chongwen Primary School, science and technology books account for 35% of the total number of libraries, and story books account for 30% of the total number of libraries, and there are 2,500 more science and technology books than story books. How many books are there in the library of Chongwen Primary School?
崇文小学图书馆中的科技书占图书馆总数的35%，故事书占图书馆总数的30%，科技书比故事书多2500本．崇文小学图书馆共藏书多少本？
<gadget id="calculator">35 / 100</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(7/20) - (3/10)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">2_500 / (1/20)</gadget>
<output>50_000</output>

<result>50_000</result>