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

### Instruction:
 Uwezo wa maktaba ya nyumbani ya Karson ni vitabu 400. Ikiwa kwa sasa ana vitabu 120, anahitaji kununua vitabu vingapi zaidi ili kufanya maktaba yake iwe imejaa 90%?


### Response:
 Ikiwa imejaa 90%, maktaba ya Karson inaweza kuhifadhi vitabu 90/100*400 = <<90/100*400=360>>360.
Ikiwa ana vitabu 120 kwenye maktaba sasa, anahitaji kununua vitabu 360-120 = <<360-120=240>>240 ili kufikia 90% ya uwezo.