The capacity of Karson's home library is 400 books. If he currently has 120 books, how many more books does he have to buy to make his library 90% full?
When 90% full, Karson's library holds 90/100*400 = <<90/100*400=360>>360 books.
If he has 120 books in the library now, he needs to buy 360-120 = <<360-120=240>>240 books to make his library 90% full.
#### 240
human
The capacity of Karson's home library is 400 books. If he currently has 120 books, how many more books does he have to buy to make his library 90% full?
gpt
When 90% full, Karson's library holds 90/100*400 = <<90/100*400=360>>360 books.
If he has 120 books in the library now, he needs to buy 360-120 = <<360-120=240>>240 books to make his library 90% full.
#### 240