To estimate the price of the 2020 Kia Optima I4 2.0L LX (Mid), I first considered the new car prices for different variants. The base model starts at SAR 78500 and the top model at SAR 124500. Given that the car in question is a mid-trim, its new price would likely be between these two values. Next, I looked at the accepted offer for a 2018 Kia Optima I4 2.4L T-GDI GT (Top) with 138500 km, which was SAR 49000. This car is older and has higher mileage, so its lower price is expected. I also considered the listed prices: a 2020 Kia Optima I4 2.0L T-GDI GT (Top) with 51000 km is listed for SAR 72500, and a 2018 model with higher mileage is listed for SAR 50500. Given the car in question is a 2020 model with 49900 km and a mid-trim, I adjusted the price down from the top-trim 2020 model listed at SAR 72500, considering the lower trim and slightly lower mileage.