Unified Parcel, Inc. operates a local parcel delivery service. The company keeps detailed records relating operating costs of trucks, and has found that if a truck is driven 110,000 kilometres per year, the operating cost is 7.5 cents per kilometre. This cost increases to 8.75 cents per kilometre if a truck is driven 60,000 kilometres per year. Required: Estimate the cost formula for truck operating costs using the high-low method