using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var data = new List<Location>()

        {

            new Location(){ 

                LocationId = 1,

                LocationName = "First Location",

                SaleTransactionList = new()

                {

                    new() { SaleTransactionId = 1, Amount = 1500, LocationId = 1 },

                    new() { SaleTransactionId = 2, Amount = 700, LocationId = 1 },

                    new() { SaleTransactionId = 3, Amount = 2400, LocationId = 1 },

                }

            },

            new Location(){ 

                LocationId = 2,

                LocationName = "Second Location",

                SaleTransactionList = new()

                {

                    new() { SaleTransactionId = 1, Amount = 120000, LocationId = 1 },

                    new() { SaleTransactionId = 2, Amount = 700.99, LocationId = 1 },

                    new() { SaleTransactionId = 3, Amount = 2520.09, LocationId = 1 },

                }

            }

        };

​

        var q = data.Select(x => new result()

                            {

                                LocationId = x.LocationId,

                                LocationName = x.LocationName,

                                Revenues = x.SaleTransactionList.Sum(s => s.Amount)

                            }).ToList();

        q.ForEach(x => {

            Console.WriteLine($"Location: {x.LocationName}  |  Revenues: {x.Revenues}");

        });

    }

    public class Location 

    {

        public int LocationId {get; set;}

        public string LocationName {get; set;}

        public List<SaleTransaction> SaleTransactionList {get; set;}

    }

    public class SaleTransaction 

    {

        public int SaleTransactionId {get; set;}

        public double Amount {get; set;}

        public double LocationId  {get; set;}

    }

    public class result 

    {

        public int LocationId {get; set;}

        public string LocationName {get; set;}

        public double Revenues {get; set;}

    }

}