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

### Instruction:
A school library has 120 books.  Each student needs 5 books for their classes.  The library was able to help 4 students on the first day of school, 5 students on the second day and 6 students on the third day.  How many students can the library help out on the fourth day of school?

### Response:
 Siku ya kwanza, maktaba ilisaidia vitabu 20 kwa sababu 4 x 5 = <<4*5=20>>20.
Siku ya pili, maktaba ilisaidia vitabu 25 kwa sababu 5 x 5 = <<5*5=25>>25.
Siku ya tatu, maktaba ilisaidia vitabu 30 kwa sababu 6 x 5 = <<6*5=30>>30.
Siku ya nne, maktaba ilikuwa na vitabu 45 vilivyosalia kwa sababu 120 - 20 - 25 - 30 = <<120-20-25-30=45>>45.
Maktaba inaweza kusaidia wanafunzi 9 siku ya nne kwa sababu 45 / vitabu 5 = <<45/5=9>>9.