To estimate the price of the 2015 Bentley Continental GT Speed W12 6.0L Twin Turbocharged Standard coupe, I started with the new car price of the 2025 Bentley Continental Standard Coupe, which is SAR 951500. Given that cars depreciate by approximately 10% per year, I calculated the depreciation over 9 years (from 2015 to 2024). The depreciation factor is 0.9^9, which is approximately 0.387. Applying this factor to the new car price, the estimated value is SAR 368731.5. Considering the car's average condition and mileage of 27700 km, I adjusted the price slightly downwards to account for these factors.