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

### Instruction:
 Ikiwa gari linaendeshwa maili 12 Jumatatu, maili 18 Jumanne, na maili 21 Jumatano. Ni umbali wa wastani uliosafiriwa kwa siku?


### Response:
 Jumla ya umbali uliosafiriwa kutoka Jumatatu hadi Jumatano ni maili 12 + 18 + 21 = <<12+18+21=51>>51.
Hivyo, umbali wa wastani uliosafiriwa kwa siku ni 51/3 = <<51/3=17>>17 maili.