This is an example of "Equilibrium in business"
Explanation:
Equilibrium is the state of balance between market supply and demand, and as a consequence, prices are stable. Over-supply of goods or services generally causes prices to fall, leading to higher demand. The offers and demand balance effect results in a stable state. Here as Denny have good retail distribution network which allow him to supply across city and maintain lower price due to good availability of ice creams. For Denny reaching to the customers was easy via vans, thus his ice-creams had lower price.