To estimate the price of the 2017 Cadillac XT5 V6 3.6L Premium Luxury (Mid) with 121000 km mileage, I considered the listed prices of similar cars. The closest match is a 2017 Cadillac XT5 V6 3.6L Premium Luxury (Mid) with 118000 km listed for SAR 85500. Another 2017 Cadillac XT5 V6 3.6L AWD Sport (Top) with 85000 km is listed for SAR 82000. A 2018 model with 85700 km is listed for SAR 103500. Given the higher mileage and average condition of the target car, I adjusted the price downwards from the closest match of SAR 85500 to account for the additional 3000 km and average condition.