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

### Instruction:
A boat is traveling across a square lake at 10 MPH. It takes 2 hours to go across the length of the lake. It then travels the whole width of the lake at the same speed, which takes 30 minutes. How many square miles is the lake?

### Response:
 Ziwa lina upana wa maili 20 kwa sababu 2 x 10 = <<2*10=20>>20
Lina urefu wa maili 5 kutoka chini hadi juu kwa sababu 20 x .25 = <<20*.25=5>>5
Ukubwa wa ekari ni 100 kwa sababu 20 x 5 = <<20*5=100>>100