40 niche articles needed

I need 40 (forty) articles in four different niches (10 per niche). Each article should have 350-400 words in length. I'll provide you with the keywords for each niche, so you'll know what to write about. The articles must be 100% unique and decent - short and informative. Also, they must be gramatically correct and pass Copyscape. Turnaround of 9-10 days. I am willing to pay $1 for each article. Please don't bid if you don't agree with the price ($40) or you don't feel able to provide the articles in time (10 days maximum). The bidders that provide samples will have a lot more chances to win.