Dear John,
Over the past six months I have written blogs, product descriptions, both long and short news articles. For a good deal longer, I have also written speeches and fiction.
Your instructions are clear. It sounds interesting. I would love to write the 100 short articles for your company.
I could probably complete it more quickly than the 90 days, but it seems wise to allow room for the odd topic that might require longer time to handle properly.
Thanks, Ugotmailu