There are 275 books in three layers on the bookshelf, the number of books on the third layer is 2 times more than that of the second layer, and the number of books on the first layer is 3 times less than that of the second layer. How many books are placed on the third floor.
在书架上摆放着三层书共275本，第三层的书比第二层的3倍多2本，第一层比第二层的2倍少3本．第三层上摆放着多少本书．
<result>89</result>