Simple problems resolved

Good morning!

I added the files with the solutions.
They were created in Visual Studio 2010.

Here is a print screen of the VS Solution if you want to reproduce it:
![vs_solution](https://cloud.githubusercontent.com/assets/8064846/3478786/0748603c-0344-11e4-9cd8-14a79bd121ac.png)

The UnitTests project needs a reference to the SimpleProblems project.

Thank you for your time.
```C#
array[Math.Abs(array[i]) - 1] * (-1)
```

I would prefer:

```C#
-1 * array[Math.Abs(array[i]) - 1] 
```