Common Lisp translation. Please review, then approve :)

I modified test cases to make the more readable and maintainable by testers.

C# translation

PHP translation is ready! Please check and approve it.

Change the kata description. It's unbearable to see how you have to re-read it, and look at the sample tests' arguments and expected results just to grasp the idea that the S, which you need to plug into the t = S/V formula, equals to 400.