GetSalesWithAppliedDiscount

 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.ToString("F2"),
                    price = x.Car.PartCars.Sum(y => y.Part.Price).ToString("F2"),
                    priceWithDiscount = (x.Car.PartCars.Sum(y => y.Part.Price)-(x.Car.PartCars.Sum(y => y.Part.Price) * x.Discount /100 )).ToString("F2")
                }).ToArray();

            var result = JsonConvert.SerializeObject(sales,Formatting.Indented);

            return result;
        }