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
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Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
You are solving math problems. Here are some examples of how to solve the task:

Mr. Fortchaud turns on his heater on the 1st of November, 2005. The fuel tank was then full and contained 3,000 L. On January 1, 2006, the tank counter indicated that 180 L remained. Mr. Fortchaud again filled his tank completely. On 1 May 2006, Mr. Fortchaud decided to stop heating and he read 1,238 L on the meter. What the volume of fuel oil that was used between 1 November 2005 and 1 May 2006?I calculate consumption between November 1, 2005 and January 1, 2006: 3,000 – 180 = <<3000-180=2820>>2820 L
I calculate consumption between January 1, 2006 and May 1, 2006: 3,000 – 1238 = <<3000-1238=1762>>1762 L
I calculate the total consumption between November 1st and May 1st: 2,820 + 1,762 = <<2820+1762=4582>>4582 L
#### 4,582[END]

Mrs. Garcia pays her insurance quarterly at $378. How much does she pay in a year for her insurance?Since there are three months in a quarter, then there are 12/3 = <<12/3=4>>4 quarters in a year.
So, Mrs. Garcia pays $378 x 4 = $<<378*4=1512>>1512 in a year for her insurance.
#### 1512[END]

Now, solve this next question in the style of the above examples:

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:
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