useful to Gower? 10-27 Estimating a cost function, high-low method. FlyHigh Vacations offers helicopter service from suburban towns to Heathrow Airport in the United Kingdom. Each of its 10 helicopters makes between 1,000 and 2,000 round-trips per year. The records indicate that a helicopter that has made 1,000 round-trips in the year incurs an average operating cost of 350 per round-trip, and one that has made 2,000 round-trips in the year incurs an average operating cost of S300 per round-trip. year incurs an average operating cost of $300 per round-trip. 1. Using the high-low method, estimate the linear relationship y = a + bx, where y is the total annual oper ating cost of a helicopter and Xis the number of round-trips it makes to Heathrow Airport during the year