compoundmethod.cs

public override float Calculate()
{
  return CalculateOverTimeHours(HoursWorked, 52, 
		x => x * OvertimeRates.Double_Time_And_A_Half) +
	base.Calculate();
}

OvertimeRates.cs

// Developer: Cory Fowler
// Company: SyntaxC4 Development Services
// Description: Adds Type Safety and Saves Memory over Class

namespace WageCalculator.Abstractions
{
    public struct OvertimeRates
    {
        public const float Regular = 1.0f;
        public const float Time_And_A_Half = 1.5f;
        public const float Double_Time = 2.0f;
        public const float Double_Time_And_A_Half = 2.5f;
    }
}

SalaryWageCalculator.cs

// Developer: Cory Fowler
// Company: SyntaxC4 Development Services
// Description: Calculates Regular Time Rates for Employees

namespace WageCalculator.Concrete
{
    public class SalaryWageCalculator : Abstractions.WageCalculatorBase
    {
        #region ctor
        public SalaryWageCalculator(float hours, float hourlyRate) : 
                    base(hours, hourlyRate) { }
        #endregion

        public override float Calculate()
        {
            return HoursWorked * HourlyRate;
        }
        
        public static float Calculate(float hours, float hourlyRate)
        {
            return new SalaryWageCalculator(hours, hourlyRate).Calculate();
        }
    }
}

TimeAndAHalfWaeCalculator.cs

// Developer: Cory Fowler
// Company: SyntaxC4 Development Services
// Description: Adds Functionality for OverTime Wage Calculation

namespace WageCalculator.Concrete
{
  #region Usings
	using Abstractions;
	#endregion

	public class TimeAndAHalfWageCalculator : WageCalculatorBase
	{
		public const float MAXIMUM_HOURS_BEFORE_TIME_AND_A_HALF = 40;

		public TimeAndAHalfWageCalculator(float hours, float hourlyRate) : base(hours, hourlyRate){}
	
		public override float Calculate()
		{
			return  (CalculateOverTimeHours(HoursWorked, 
						MAXIMUM_HOURS_BEFORE_TIME_AND_A_HALF, 
                        x => x * OvertimeRates.Time_And_A_Half) +
					MAXIMUM_HOURS_BEFORE_TIME_AND_A_HALF) * HourlyRate;
		}

		public static float Calculate(float hours, float hourlyRate)
		{
			return new TimeAndAHalfWageCalculator(hours, hourlyRate).Calculate();
		}
	}
}

WageCalculatorBase.cs

// Developer: Cory Fowler
// Company: SyntaxC4 Development Services
// Description: Exposes Common Functionality to WageCalculators.

namespace WageCalculator.Abstractions
{
    #region Usings
    using System;
    #endregion

    public abstract class WageCalculatorBase
    {
        public float HoursWorked { get; private set; }
        public float HourlyRate { get; private set; }

        public const float MAXIMUM_HOURS_PER_WEEK = 80f;
        public const float MINIMUM_HOURS_PER_WEEK = 0f;
        
        public WageCalculatorBase(float hours, float hourlyRate)
        {
            if (hours < MINIMUM_HOURS_PER_WEEK || hours > MAXIMUM_HOURS_PER_WEEK)
                // Should Probably Create WorkWeekOutOfRangeException
                throw new ArgumentOutOfRangeException(string.Format("Hours must be between {0} and {1}",
                                                                                MINIMUM_HOURS_PER_WEEK,
                                                                                MAXIMUM_HOURS_PER_WEEK));
            HoursWorked = hours;
            HourlyRate = hourlyRate;
        }

        protected float CalculateOverTimeHours(float hours, 
                                               float overtimeThreshold, 
                                               Func<float, float> calculateOvertimePay)
        {
            return calculateOvertimePay(hours - overtimeThreshold);
        }

        public abstract float Calculate();
    }
}