There were some books in the "Book Corner". After lending 10 books, the school distributed 70 new books. The result was 50% more than the original ones. How many books did the "Book Corner" have?
"图书角"原有一些书，借出10本后，学校又新配发了70本新书，结果比原来多50%，"图书角"原有多少本书．
<gadget id="calculator">70 - 10</gadget>
<output>60</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">60 / (1/2)</gadget>
<output>120</output>

<result>120</result>