Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
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?

### Response:
Last year, there were a total of 100 + 50 = <<100+50=150>>150 books in the library.
The library purchased 50 x 3 = <<50*3=150>>150 books this year.
Therefore, there are a total of 150 + 150 = <<150+150=300>>300 books in the library now.
#### 300