So, he gathers the vendors and asks if they would agree to only sell cakes on the first day of the week, as this is the day when cakes are in demand, further he asks if they would agree to sell cakes for a price of $1 as they are free to set their price. If a majority of the vendors are selling at $1 the buyers will have no choice but to buy cake at $1 after the lower priced cakes are gone; in this way the 'union' of vendors make more money selling their cakes for $1 on the first day when demand is highest; as opposed to selling their cakes individually;