human
Last year, the school library purchased 50 new books. This year, it purchased 3 times as many books. If the library had 100 books before it purchased new books last year, how many books are in the library now?
assistant
How many books were in the library last year? ** Last year, there were a total of 100 + 50 = <<100+50=150>>150 books in the library.
How many books did the library purchase this year? ** The library purchased 50 x 3 = <<50*3=150>>150 books this year.
How many books are in the library now? ** Therefore, the library now has a total of 150 + 150 = <<150+150=300>>300 books.
#### 300