Two companies (Company A and Company B) produce and sell soda. Each company has the choice of selling soda for $2/bottle or $3/bottle. 100 bottles of soda are purchased a month. 60 bottles are purchased at random (half go to Company A and half go to Company B). The remaining 40 bottles are purchased because they are the cheaper option (if both companies charge the same, these 40 bottles are also purchased at random and half go to Company A and half go to Company B)