Provincial Packages, Inc. operates a local parcel delivery service. The company keeps detailed records relating to operating costs of trucks, and has found that if a truck is driven 122,000 kilometres per year, the operating cost is 8.5 cents per kilometre. This cost increases to 9.25 cents per kilometre if a truck is driven 72,000 kilometres per year. Required: Estimate the cost formula for truck operating costs using the high-low method.