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

### Instruction:
Ava planted 9 apple trees in her backyard. That's 3 more than Lily planted in her backyard. How many apple trees did they plant in their backyards collectively?

### Response:
 Kwa kuwa Ava alipanda miti 3 zaidi ya Lily, Lily alipanda miti 9-3 = <<9-3=6>>6 ya miti ya apple kwenye nyuma ya nyumba yake.
Kwa pamoja, walipanda miti 6+9 = <<6+9=15>>15 ya miti ya apple kwenye nyuma ya nyumba zao.