On a shelf, books with green cover and that with brown cover are in the ratio 2:3. If there are 18 books with green cover, then the number of books with brown cover is


As the simplest form of the ratio is 2:3


Therefore the common factor of 2 and 3 can be taken as x.


Therefore 2x = 18


x = 9


Therefore number of books with brown cover = 3x9 = 27

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