gistfile1.cs

    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Sal = {0}, Taxes = {1}", 5000, Taxes(5000));
            Console.WriteLine("Sal = {0}, Taxes = {1}", 5800, Taxes(5800));
            Console.WriteLine("Sal = {0}, Taxes = {1}", 9000, Taxes(9000));
            Console.WriteLine("Sal = {0}, Taxes = {1}", 15000, Taxes(15000));
            Console.WriteLine("Sal = {0}, Taxes = {1}", 50000, Taxes(50000));
            Console.ReadLine();
        }
        static decimal Taxes(decimal sal)
        {
            Tuple<decimal, decimal>[] rates = 
            { 
                new Tuple<decimal, decimal>(0m, 0.1m), 
                new Tuple<decimal, decimal>(5070m, 0.14m),
                new Tuple<decimal, decimal>(8660m, 0.23m),
                new Tuple<decimal, decimal>(14070m, 0.30m),
                new Tuple<decimal, decimal>(21240m, 0.33m),
                new Tuple<decimal, decimal>(40230m, 0.45m) 
            };
            return rates.Reverse().Select(bracket => 
                { 
                    var amt = Math.Max(0, sal - bracket.Item1); 
                    sal -= amt; 
                    return amt * bracket.Item2; 
                }).Sum();
        }
    }