Competitor price reduced this for McDonalds. Burger king for example, have decrease the price of Whooper by 75% and not essential the fries and drinks to be purchased. It is known that McDonald's is a rational competitor; BK knew that it would not reduce the price any deeper as this would incite a price war and ruined the market of all the players. At this point, McDonald's best would be discontinued its promotion of price, thus signaling to BK. With this signal, the competitors could increase the price and restore the profitability of the industry to level it was before the McDonald's initial price cut