In 2009, the number of books read library of the boys is 50, grils is 30. By 2010, increasing the number of boys is 80, grils increase is 40. In 2011, the number of books read library of the boys and grils are equal to 100. And in 2012, the number of books read library of the grils unexpectedly increased the book is 140 boys, boys dropped to 80 books.
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