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

### Instruction:
Melody has three dogs. Each dog eats 1/2 of a pound of dog food twice a day. If Melody bought 30 pounds of dog food, how many pounds of dog food are left after a week?

### Response:
 Kila mbwa hula 1/2 x 2 = <<1/2*2=1>>1 pauni ya chakula cha mbwa kila siku.
Hivyo, matumizi ya chakula cha mbwa kwa wiki ya mbwa watatu ni 3 x 7 = <<3*7=21>>21 pauni.
Hivyo, pauni 30 - 21 = <<30-21=9>>9 za chakula cha mbwa zimebaki baada ya wiki moja.