Megabus must plan its fleet design capacity and its long-term schedule of bus usage. For the trip from DC to New York, the average number of occupied seats by customers per day is 32, which represents an 80 percent design utilization rate of the seats assigned to the trip. Assume that management deems to keep the design capacity utilization rate below 90 percent. If the average demand is expected to increase to 40 customers per day for DC-New York trip in three years, how many seats should be added to the design capacity of the bus?