How much do you think I can lose with this program?

I ordered the Jillian Michaels 30 Day Shred DVD and am going to start it on July 25th. I'm already on a diet and have lost 10 pounds. I've been eating 1200 calories a day and exercising. If I continue this regimen while doing the 30 Day Shred, could I lose 15 more pounds by September 8th? My goal weight is to be 100 pounds on that date.