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?
The lake is 20 miles across because 2 x 10 = <<2*10=20>>20
If takes .5 hours to go from bottom to top because 30 / 60 = <<30/60=.5>>.5
The lake is five miles from bottom to top because 10 x .5 = <<10*.5=5>>5
The square mileage is 100 because 20 x 5 = <<20*5=100>>100
#### 100