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

### Instruction:
 Mdogo wangu na mimi tuna dakika thelathini kwenda shule, bila kuchelewa. Inatuchukua dakika kumi na tano kufika kwenye lango la shule, na dakika sita nyingine kufika jengo la shule. Tunayo muda gani wa kufika darasani, bila kuchelewa?


### Response:
 Jumla ya muda tuliotumia kwenda shule ni dakika kumi na tano + dakika sita = <<15+6=21>>21 dakika.
Tunayo dakika thelathini - dakika ishirini na moja = <<30-21=9>>9 dakika zilizobaki ili tusichelewe.