To estimate the price of the 2015 Infiniti QX60 V6 3.5L Luxe Sensory (Top) with 173000 km mileage in average condition, I first considered the selling price of a similar car with 115000 km mileage in good condition, which sold for SAR 64500 on 2023-10-24. Given the higher mileage and average condition of the target car, I adjusted the price downwards. Next, I looked at listed prices of similar cars: one with the same mileage listed for SAR 52500, another with 192000 km listed for SAR 60000, and another with 135000 km listed for SAR 64000. Considering the average condition and higher mileage, I estimated the price to be slightly lower than these listings. Finally, I factored in the general trend of listed prices for similar cars, which ranged from SAR 40000 to SAR 110000, with most relevant listings around SAR 50000 to SAR 60000.