A veterinarian is changing the diets of two animals, Lady and Bina. Lady currently consumes 1000 calories per day. She will increase her diet by 100 calories each day. Bina currently consumes 3600 calories a day, and her diet will decrease by 200 calories each day. If these patterns continue for both animals, in how many days, d, will Lady consume half of the number of calories that Bina consumes?