450 words articles

I need 50 UNIQUE high quality articles: -40 of them keyword based. Each must contain the keyword 4-5 times at least, and must be at least 450 words long. I will give the keywords after i choose the writer. The articles must contain the keywords and long tail keywords which i will choose. -the other 10 can be chosen by the writer but must respect any article directory guideline and also must have 450 words. I need them done in 2 weeks and the buget is around 100 dollars.