Construction of Original GMAT Math Questions

Hi there,

I have the objective to set-up a list of original GMAT questions focusing on the Quantitative Section of the test.

First, here some key experiences and skills necessary for the project :

1) Strong quantitative/maths skills (algebra, arithmetic, geometry)
2) Experience of GMAT with solid score

The idea is following: lot of questions are available on line, I need to reformulate the questions to propose a set of reformulated ones not violating copyrighting.

For the nature of questions, only arithmetic, algebra and geometry.

Here example of original question: http://icecream.me/61fcd21ca699a63ac20efcb483278678
Here an example of reformulation : http://icecream.me/461318d82fa6f53c1c7384922ffdd8e6

Please notice:
1) This type of modification, where the underlying concept being tested is the same and even the format of the answer choices are the same, is acceptable.
2) Just changing figures is not acceptable
3) I need also to reformulate the solutions according to the new figures you will choose

Process to follow:
1) Build a power point document to list all questions by copying in the pdf enclosed
2) For each question, read carrefully the answer and understand it
3) Change value of some figures, rename the parameter as illustrated above
4) Rewrite the question & the solution on the ppt
5) Now we have an original one and we continue with the next

I would like to start with a set of 50 questions/solutions reformulated.

Please propose me your fair price.
Please read carrefully this message and the resources associated.
Prally only apply if you're good in maths and know already GMAT

Thanks & Best

vhm