diff --git a/week-1/day-2/exercise-1/Circle/Circle.cs b/week-1/day-2/exercise-1/Circle/Circle.cs
index 065ffa5d..9d9e2fd1 100644
--- a/week-1/day-2/exercise-1/Circle/Circle.cs
+++ b/week-1/day-2/exercise-1/Circle/Circle.cs
@@ -9,5 +9,22 @@ namespace Circle
     internal class Circle
     {
         // Implement the Circle class here
+        public double Radius { get; private set; }
+
+        public Circle(double radius)
+        {
+            Radius = radius;
+        }
+
+        public double GetArea()
+        {
+            return Math.PI * Math.Pow(Radius, 2);
+        }
+
+        public double GetCircumference()
+        {
+            return 2 * Math.PI * Radius;
+        }
+
     }
 }
diff --git a/week-1/day-2/exercise-1/Circle/Program.cs b/week-1/day-2/exercise-1/Circle/Program.cs
index 0df91b0d..d7a5f941 100644
--- a/week-1/day-2/exercise-1/Circle/Program.cs
+++ b/week-1/day-2/exercise-1/Circle/Program.cs
@@ -4,7 +4,17 @@ internal class Program
     {
         static void Main(string[] args)
         {
-            // Create a Circle object and display its area and circumference
+            // Create a Circle object with a given radius
+            double radius = 5.0;
+            Circle circle = new Circle(radius);
+
+            // Calculate and display the area
+            double area = circle.GetArea();
+            Console.WriteLine($"Area of the circle with radius {radius}: {area}");
+
+            // Calculate and display the circumference
+            double circumference = circle.GetCircumference();
+            Console.WriteLine($"Circumference of the circle with radius {radius}: {circumference}");
         }
     }
 }
\ No newline at end of file
diff --git a/week-1/day-2/exercise-2/BankAccount/Program.cs b/week-1/day-2/exercise-2/BankAccount/Program.cs
index c58c30e2..84f485ad 100644
--- a/week-1/day-2/exercise-2/BankAccount/Program.cs
+++ b/week-1/day-2/exercise-2/BankAccount/Program.cs
@@ -1,10 +1,90 @@
-namespace BankAccount
+using System;
+
+public abstract class BankAccount
 {
-    internal class Program
+    public string AccountNumber { get; protected set; }
+    public double Balance { get; protected set; }
+
+    public BankAccount(string accountNumber, double initialBalance)
     {
-        static void Main(string[] args)
+        AccountNumber = accountNumber;
+        Balance = initialBalance;
+    }
+
+    public abstract void Deposit(double amount);
+    public abstract void Withdraw(double amount);
+}
+
+public class SavingsAccount : BankAccount
+{
+    public double InterestRate { get; private set; }
+
+    public SavingsAccount(string accountNumber, double initialBalance, double interestRate)
+        : base(accountNumber, initialBalance)
+    {
+        InterestRate = interestRate;
+    }
+
+    public override void Deposit(double amount)
+    {
+        Balance += amount;
+    }
+
+    public override void Withdraw(double amount)
+    {
+        if (Balance >= amount)
+        {
+            Balance -= amount;
+        }
+        else
         {
-            // Create SavingsAccount and CheckingAccount objects and perform operations
+            Console.WriteLine("Insufficient balance.");
         }
     }
-}
\ No newline at end of file
+}
+
+public class CheckingAccount : BankAccount
+{
+    public double OverdraftLimit { get; private set; }
+
+    public CheckingAccount(string accountNumber, double initialBalance, double overdraftLimit)
+        : base(accountNumber, initialBalance)
+    {
+        OverdraftLimit = overdraftLimit;
+    }
+
+    public override void Deposit(double amount)
+    {
+        Balance += amount;
+    }
+
+    public override void Withdraw(double amount)
+    {
+        if (Balance + OverdraftLimit >= amount)
+        {
+            Balance -= amount;
+        }
+        else
+        {
+            Console.WriteLine("Insufficient balance.");
+        }
+    }
+}
+
+class Program
+{
+    static void Main(string[] args)
+    {
+        SavingsAccount savingsAccount = new SavingsAccount("SA123", 1000, 0.05);
+        CheckingAccount checkingAccount = new CheckingAccount("CA456", 500, 200);
+
+        savingsAccount.Deposit(500);
+        savingsAccount.Withdraw(200);
+
+        checkingAccount.Deposit(300);
+        checkingAccount.Withdraw(800);
+
+        Console.WriteLine($"Savings Account Balance: {savingsAccount.Balance}");
+        Console.WriteLine($"Checking Account Balance: {checkingAccount.Balance}");
+    }
+}
diff --git a/week-1/day-2/exercise-3/AnimalExercise/Program.cs b/week-1/day-2/exercise-3/AnimalExercise/Program.cs
index 5928b7cb..756e8b2c 100644
--- a/week-1/day-2/exercise-3/AnimalExercise/Program.cs
+++ b/week-1/day-2/exercise-3/AnimalExercise/Program.cs
@@ -1,10 +1,66 @@
-namespace AnimalExercise
+using System;
+using System.Collections.Generic;
+
+public abstract class Animal
 {
-    internal class Program
+    public string Name { get; set; }
+    public int Age { get; set; }
+
+    public abstract void MakeSound();
+}
+
+public class Dog : Animal, IMovable
+{
+    public override void MakeSound()
+    {
+        Console.WriteLine("Woof");
+    }
+
+    public void Move()
     {
-        static void Main(string[] args)
+        Console.WriteLine("Dog is running.");
+    }
+}
+
+public class Cat : Animal, IMovable
+{
+    public override void MakeSound()
+    {
+        Console.WriteLine("Meow");
+    }
+
+    public void Move()
+    {
+        Console.WriteLine("Cat is sneaking.");
+    }
+}
+
+public interface IMovable
+{
+    void Move();
+}
+
+class Program
+{
+    static void Main(string[] args)
+    {
+        List<Animal> animals = new List<Animal>
+        {
+            new Dog { Name = "Buddy", Age = 3 },
+            new Cat { Name = "Whiskers", Age = 2 }
+        };
+
+        foreach (var animal in animals)
         {
-            // Create a list of Animal objects, add Dog and Cat instances, and call their methods
+            Console.WriteLine($"Name: {animal.Name}, Age: {animal.Age}");
+            animal.MakeSound();
+
+            if (animal is IMovable movableAnimal)
+            {
+                movableAnimal.Move();
+            }
+
+            Console.WriteLine();
         }
     }
-}
\ No newline at end of file
+}
diff --git a/week-1/day-2/exercise-4/VehicleManagementSystem/Program.cs b/week-1/day-2/exercise-4/VehicleManagementSystem/Program.cs
index 77395b3a..add6361c 100644
--- a/week-1/day-2/exercise-4/VehicleManagementSystem/Program.cs
+++ b/week-1/day-2/exercise-4/VehicleManagementSystem/Program.cs
@@ -1,10 +1,198 @@
-namespace VehicleManagementSystem
+using System;
+using System.Collections.Generic;
+
+// 1. IVehicle interface
+public interface IVehicle
 {
-    internal class Program
+    void Drive();
+}
+
+// 2. Car and Truck classes
+public class Car : IVehicle
+{
+    public void Drive()
+    {
+        Console.WriteLine("Car is driving.");
+    }
+}
+
+public class Truck : IVehicle
+{
+    public void Drive()
+    {
+        Console.WriteLine("Truck is driving.");
+    }
+}
+
+// 3. Singleton VehicleLogger class
+public class VehicleLogger
+{
+    private static VehicleLogger instance;
+    private VehicleLogger() { }
+
+    public static VehicleLogger Instance
+    {
+        get
+        {
+            if (instance == null)
+            {
+                instance = new VehicleLogger();
+            }
+            return instance;
+        }
+    }
+
+    public void Log(string message)
+    {
+        Console.WriteLine($"[Log] {message}");
+    }
+}
+
+// 4. Abstract VehicleFactory class
+public abstract class VehicleFactory
+{
+    public abstract IVehicle CreateVehicle();
+
+    public void DoSomethingWithVehicle()
+    {
+        IVehicle vehicle = CreateVehicle();
+        vehicle.Drive();
+    }
+}
+
+// 5. Concrete factory classes
+public class CarFactory : VehicleFactory
+{
+    public override IVehicle CreateVehicle()
+    {
+        return new Car();
+    }
+}
+
+public class TruckFactory : VehicleFactory
+{
+    public override IVehicle CreateVehicle()
+    {
+        return new Truck();
+    }
+}
+
+// 6. IRepository interface
+public interface IRepository<T>
+{
+    T GetById(int id);
+    IEnumerable<T> GetAll();
+    void Add(T entity);
+    void Update(T entity);
+    void Delete(T entity);
+}
+
+// 7. VehicleRepository class
+public class VehicleRepository : IRepository<IVehicle>
+{
+    private List<IVehicle> vehicles = new List<IVehicle>();
+
+    public IVehicle GetById(int id)
+    {
+        return vehicles.FirstOrDefault(v => v.GetHashCode() == id);
+    }
+
+    public IEnumerable<IVehicle> GetAll()
+    {
+        return vehicles;
+    }
+
+    public void Add(IVehicle entity)
+    {
+        vehicles.Add(entity);
+    }
+
+    public void Update(IVehicle entity)
+    {
+        // Implement update logic
+    }
+
+    public void Delete(IVehicle entity)
+    {
+        vehicles.Remove(entity);
+    }
+}
+
+// 8. VehicleService class
+public class VehicleService
+{
+    private IRepository<IVehicle> repository;
+    private VehicleLogger logger;
+
+    public VehicleService(IRepository<IVehicle> repository)
+    {
+        this.repository = repository;
+        logger = VehicleLogger.Instance;
+    }
+
+    public void AddVehicle(VehicleFactory factory)
     {
-        static void Main(string[] args)
+        IVehicle vehicle = factory.CreateVehicle();
+        repository.Add(vehicle);
+        logger.Log($"Added a new {vehicle.GetType().Name}");
+    }
+
+    public void RemoveVehicle(int id)
+    {
+        IVehicle vehicle = repository.GetById(id);
+        if (vehicle != null)
+        {
+            repository.Delete(vehicle);
+            logger.Log($"Removed {vehicle.GetType().Name}");
+        }
+        else
         {
-            Console.WriteLine("Hello, World!");
+            logger.Log("Vehicle not found.");
         }
     }
-}
\ No newline at end of file
+
+    public void ListVehicles()
+    {
+        foreach (var vehicle in repository.GetAll())
+        {
+            Console.WriteLine($"Vehicle: {vehicle.GetType().Name}");
+        }
+    }
+
+    public void DoSomethingWithVehicle(int id)
+    {
+        IVehicle vehicle = repository.GetById(id);
+        if (vehicle != null)
+        {
+            vehicle.Drive();
+            logger.Log($"Performed action on {vehicle.GetType().Name}");
+        }
+        else
+        {
+            logger.Log("Vehicle not found.");
+        }
+    }
+}
+
+class Program
+{
+    static void Main(string[] args)
+    {
+        IRepository<IVehicle> repository = new VehicleRepository();
+        VehicleService service = new VehicleService(repository);
+
+        VehicleFactory carFactory = new CarFactory();
+        VehicleFactory truckFactory = new TruckFactory();
+
+        service.AddVehicle(carFactory);
+        service.AddVehicle(truckFactory);
+
+        service.ListVehicles();
+
+        service.DoSomethingWithVehicle(1);
+        service.DoSomethingWithVehicle(2);
+
+        service.RemoveVehicle(1);
+        service.ListVehicles();
+    }
+}
diff --git a/week-1/day-3/exercise-1/FactorialApp/Program.cs b/week-1/day-3/exercise-1/FactorialApp/Program.cs
index f116eeca..aced81db 100644
--- a/week-1/day-3/exercise-1/FactorialApp/Program.cs
+++ b/week-1/day-3/exercise-1/FactorialApp/Program.cs
@@ -12,9 +12,20 @@ public static void Main()
             Console.WriteLine($"The factorial of {number} is: {factorial}");
         }
 
-        public static long CalculateFactorial(int number)
+        public static long CalculateFactorial(int n )
         {
-            throw new NotImplementedException();
+            if (n == 0 || n == 1)
+            {
+                return 1;
+            }
+
+            long result = 1;
+            for (int i = 2; i <= n; i++)
+            {
+                result *= i;
+            }
+
+            return result;
         }
     }
 }
\ No newline at end of file
diff --git a/week-1/day-3/exercise-2/ShortesPathAlgorithm/Program.cs b/week-1/day-3/exercise-2/ShortesPathAlgorithm/Program.cs
index a4ec62d9..8c02d7d6 100644
--- a/week-1/day-3/exercise-2/ShortesPathAlgorithm/Program.cs
+++ b/week-1/day-3/exercise-2/ShortesPathAlgorithm/Program.cs
@@ -223,7 +223,7 @@ public int[] DijkstraShortestPath(int source)
                 visited[i] = false;
             }
 
-            distances[source] = int.MinValue;
+            distances[source] = 0;
 
             for (int count = 0; count < vertices - 1; count++)
             {