using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    class Person {

        public int Age { get; set; }

        public string Name { get; set; }

    }

    public static void Main()

    {

        var test = new List<Person>

        { 

            new Person { Name = "Andrew", Age = 20 },

            new Person { Name = "Jess", Age = 26 },

            new Person { Name = "John", Age = 28 },

            new Person { Name = "Tom", Age = 28 },

            new Person { Name = "Melissa", Age = 27 },

        };

        test.Aggregate(new List<string>(), (validNames, next) => {

            if (next.Age < 28)

            {

                validNames.Add(next.Name);

            }

            return validNames;

        }).ForEach(Console.WriteLine);

    }

}

​