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

### Instruction:
 Marianne alikuwa na miaka 20 wakati Bella alikuwa na miaka 8. Marianne atakuwa na miaka mingapi wakati Bella atatimiza miaka 18?


### Response:
 Marianne ni miaka 20 - 8 = <<20-8=12>>12 zaidi ya Bella.
Bella atatimiza miaka 18 baada ya miaka 18 - 8 = <<18-8=10>>10.
Hivyo, Marianne atakuwa na miaka 20 + 10 = <<20+10=30>>30 wakati huo.