@Maddus Mattus: In the real world, finding an existing solution is okay under some circumstances, because then you can say "we don't have to do this work because I found this, let's focus on the new bits".
In school, there are no new bits. Everything you're solving has been solved by someone before. The reason you're solving it now is to test your understanding of the underlying principles and your ability to solve those kinds of problems.
The ability to find the solution to a problem is not the same as the ability to solve it. Would you hire someone whose only skill is finding other people's solutions, but who is incapable of doing any creative thinking of his/her own?
How would you test someone's ability to solve a problem if you can't restrict the conditions of the test such that they can't ask someone else to solve it for them?
If you are asked to solve a problem during a job interview, is it acceptable to go to Google, and copy/paste an existing solution as "your" answer?
If you ask me "what is 5+4" and I paste that in WolframAlpha and tell you the answer is 9, have you learned anything about my understanding of arithmetic?