50 articles needed fast!

I need 50 original articles created between 400-500 words each on keywords that I will choose. There will be 5 total subjects with 10 articles needed for each subject. I need the articles within 72 hours. My budget is $2 per article. Please do not bid if you cannot do for $2 per article or will take you longer than 3 days. The articles need to be in plain text with the file name being the keyword I provide for each article. The title of the articles will need to utilize the keywords I provide but be more appealing to a reader. The articles need to be in US based English and should contain a keyword density of roughly 5%. No more than 5% ! Additional keywords related to the core keyword should be used in the article. If you are not familiar with keyword density or basic SEO principles when article writing, please don't bid. Real people will be reading these articles so they should be interesting/informative to read, not just filler copy. The rights to the article will be mine once I pay you in full. All articles will be checked using copyscape so do not plagiarize. Articles that aren't original or take longer than 3 days will not be paid for. Please provide copies of previous work and any additional background information you feel would benefit you. Potential long term relationship for quality writers.