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

### Instruction:
 Milton ana vitabu kadhaa kuhusu zoology na vitabu vinne zaidi kuhusu botany. Ikiwa ana jumla ya vitabu 80, anayo vitabu vingapi vya zoology?


### Response:
 Hebu tuchukue z kuwa idadi ya vitabu vya zoology na b kuwa idadi ya vitabu vya botany. Tunajua kwamba z + b = 80 na b = 4z.
Tukibadilisha equation ya pili katika equation ya kwanza, tunapata z + 4z = 80
Tukichanganya vipengele kama, tunapata 5z = 80
Tukigawanya pande zote mbili kwa 5, tunapata z = 16