problem 17

        public static string GetSalesWithAppliedDiscount(CarDealerContext context)
        {
            var sales = context.Sales
                .Take(10)
                .Select(x => new
                {
                    car = new
                    {
                        Make = x.Car.Make,
                        Model = x.Car.Model,
                        TravelledDistance = x.Car.TravelledDistance
                    },

                    customerName = x.Customer.Name,
                    Discount = $"{x.Discount:F2}",
                    price = $"{x.Car.PartCars.Sum(y => y.Part.Price):F2}",
                    priceWithDiscount = $"{x.Car.PartCars.Sum(y => y.Part.Price) - (x.Car.PartCars.Sum(y => y.Part.Price) * (x.Discount / 100)):F2}",
                })
                .ToList();

            string json = JsonConvert.SerializeObject(sales,Formatting.Indented);

            return json;
        }