This e-mail came fairly recently and really amused me (most of them do at this point). In my mind it seems the author is new to the submission experience and will probably learn the hard way what this is all about.
I couldn't believe it when I saw that your response time is 10 week! That means that I can onl show my work five times a year. Do you really think that's fair to a writer? It would take us years to sell a book.10 weeks. Honestly, if only I were that fast (as many of you can attest to). There are certainly some submissions I get to within 10 minutes, and others . . . well, they pile up faster than I can get to them.
This touches a little on previous posts (many of them will), but since BookEnds never, ever asks for exclusives, our shamefully slow turnaround time should in no way impact how many agents you can show your work to, and therefore, if your work is going to make you some money, then we shouldn't be the ones to slow you down. And this goes for most agents as well as BookEnds.
To answer your question more specifically . . . you could send your work to 500 agents in a year and still not sell the book. As many authors can attest to (many of our own as well as bestsellers like John Grisham), finding an agent and then selling a book are two completely different things, and both can take years. If you start to figure out what you should be making monetarily based on the hours you spend writing and submitting your work, you're in for a very unpleasant surprise—minimum wage is probably going to look good.
Patience is a virtue in the game of publishing, and if you know anything about how publishers pay, finding an agent and even a publisher doesn't necessarily pay off as much as one would like.