diff --git a/assignment5/Question2/StartGrading.java b/assignment5/Question2/StartGrading.java
index 3e27226..9a9082b 100644
--- a/assignment5/Question2/StartGrading.java
+++ b/assignment5/Question2/StartGrading.java
@@ -4,34 +4,32 @@ public class StartGrading {
 //The Vehicle class is abstract. We cannot create objects from this class. Therefore, we cannot test anything
 	}
 
-
 	public static void testCar() {
 		// test case for constructors
 		try {
-// exception
+			// exception
 			Car c1 = new Car(70, 80);
 		} catch (BadSpeedSetting e) {
 			System.out.println(e.getMessage().equals("Speed cannot be greater than speed limit!"));
 		}
 		try {
-// exception
+			// exception
 			Car c2 = new Car(70, -10);
 		} catch (BadSpeedSetting e) {
 			System.out.println(e.getMessage().equals("Speed cannot be negative!"));
 		}
-// test case for accelerate, canFly and getSpeed methods
+		// test case for accelerate, canFly and getSpeed methods
 		try {
 			Car c3 = new Car(100, 80);
-// test the canFly method
+			// test the canFly method
 			System.out.println(c3.canFly() == false);
 			c3.accelerate(10);
 			System.out.println(c3.getSpeed() == 90);
-// test the accelerate with positive amount
+			// test the accelerate with positive amount
 			c3.accelerate(-20);
 			System.out.println(c3.getSpeed() == 70);
-// test the accelerate with negative amount 
-			c3.accelerate(35);
-// exception 
+			// test the accelerate with negative amount
+			c3.accelerate(35); // exception
 		} catch (BadSpeedSetting e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		} catch (ExceedSpeedLimit e) {
@@ -42,7 +40,7 @@ public class StartGrading {
 		}
 		try {
 			Car c4 = new Car(100, 80);
-// exception
+			// exception
 			c4.accelerate(-90);
 		} catch (BadSpeedSetting e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
diff --git a/assignment5/Question3/StartGrading.java b/assignment5/Question3/StartGrading.java
index 44c9673..3c0b051 100644
--- a/assignment5/Question3/StartGrading.java
+++ b/assignment5/Question3/StartGrading.java
@@ -7,30 +7,29 @@ public class StartGrading {
 	public static void testCar() {
 		// test case for constructors
 		try {
-// exception
+			// exception
 			Car c1 = new Car(70, 80);
 		} catch (BadSpeedSetting e) {
 			System.out.println(e.getMessage().equals("Speed cannot be greater than speed limit!"));
 		}
 		try {
-// exception
+			// exception
 			Car c2 = new Car(70, -10);
 		} catch (BadSpeedSetting e) {
 			System.out.println(e.getMessage().equals("Speed cannot be negative!"));
 		}
-// test case for accelerate, canFly and getSpeed methods
+		// test case for accelerate, canFly and getSpeed methods
 		try {
 			Car c3 = new Car(100, 80);
-// test the canFly method
+			// test the canFly method
 			System.out.println(c3.canFly() == false);
 			c3.accelerate(10);
 			System.out.println(c3.getSpeed() == 90);
-// test the accelerate with positive amount
+			// test the accelerate with positive amount
 			c3.accelerate(-20);
 			System.out.println(c3.getSpeed() == 70);
-// test the accelerate with negative amount 
-			c3.accelerate(35);
-// exception 
+			// test the accelerate with negative amount
+			c3.accelerate(35); // exception
 		} catch (BadSpeedSetting e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		} catch (ExceedSpeedLimit e) {
@@ -41,7 +40,7 @@ public class StartGrading {
 		}
 		try {
 			Car c4 = new Car(100, 80);
-// exception
+			// exception
 			c4.accelerate(-90);
 		} catch (BadSpeedSetting e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
diff --git a/assignment5/Question4/StartGrading.java b/assignment5/Question4/StartGrading.java
index c4006dd..ef2cf61 100644
--- a/assignment5/Question4/StartGrading.java
+++ b/assignment5/Question4/StartGrading.java
@@ -1,3 +1,4 @@
+//Q4
 public class StartGrading {
 	public static void testVehicle() {
 //The Vehicle class is abstract. We cannot create objects from this class. Therefore, we cannot test anything
@@ -6,30 +7,29 @@ public class StartGrading {
 	public static void testCar() {
 		// test case for constructors
 		try {
-// exception
+			// exception
 			Car c1 = new Car(70, 80);
 		} catch (BadSpeedSetting e) {
 			System.out.println(e.getMessage().equals("Speed cannot be greater than speed limit!"));
 		}
 		try {
-// exception
+			// exception
 			Car c2 = new Car(70, -10);
 		} catch (BadSpeedSetting e) {
 			System.out.println(e.getMessage().equals("Speed cannot be negative!"));
 		}
-// test case for accelerate, canFly and getSpeed methods
+		// test case for accelerate, canFly and getSpeed methods
 		try {
 			Car c3 = new Car(100, 80);
-// test the canFly method
+			// test the canFly method
 			System.out.println(c3.canFly() == false);
 			c3.accelerate(10);
 			System.out.println(c3.getSpeed() == 90);
-// test the accelerate with positive amount
+			// test the accelerate with positive amount
 			c3.accelerate(-20);
 			System.out.println(c3.getSpeed() == 70);
-// test the accelerate with negative amount 
-			c3.accelerate(35);
-// exception 
+			// test the accelerate with negative amount
+			c3.accelerate(35); // exception
 		} catch (BadSpeedSetting e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		} catch (ExceedSpeedLimit e) {
@@ -37,10 +37,12 @@ public class StartGrading {
 					.println(e.getMessage().equals("Current speed is 70. Accelerate 35 will exceed the speed limit!"));
 		} catch (NotEnoughSpeed e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
+		} catch (TrainSpeedChange e) {
+			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		}
 		try {
 			Car c4 = new Car(100, 80);
-// exception
+			// exception
 			c4.accelerate(-90);
 		} catch (BadSpeedSetting e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
@@ -48,6 +50,8 @@ public class StartGrading {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		} catch (NotEnoughSpeed e) {
 			System.out.println(e.getMessage().equals("Current speed is " + 80 + ", not enough speed to decelerate!"));
+		} catch (TrainSpeedChange e) {
+			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		}
 	}
 
@@ -101,6 +105,8 @@ public class StartGrading {
 					e.getMessage().equals("Current speed is 100. Accelerate 650 will exceed the speed limit!"));
 		} catch (NotEnoughSpeed e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
+		} catch (TrainSpeedChange e) {
+			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		}
 		try {
 			Aircraft a5 = new Aircraft(700, 200, 100);
@@ -114,6 +120,8 @@ public class StartGrading {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		} catch (NotEnoughSpeed e) {
 			System.out.println(e.getMessage().equals("Current speed is " + 200 + ", not enough speed to decelerate!"));
+		} catch (TrainSpeedChange e) {
+			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		}
 	}
 
@@ -123,7 +131,7 @@ public class StartGrading {
 			// exception
 			Train t1 = new Train(350, 400);
 		} catch (BadSpeedSetting e) {
-			System.out.println(e.getMessage().equals("Speed cannot be greater than	speed limit!"));
+			System.out.println(e.getMessage().equals("Speed cannot be greater than speed limit!"));
 		}
 		try {
 			// exception
@@ -150,7 +158,7 @@ public class StartGrading {
 	public static void main(String[] args) {
 		Vehicle.testVehicle();
 		Car.testCar();
-		AirCraft.testAirCraft();
+		Aircraft.testAircraft();
 		Train.testTrain();
 	}
 }
diff --git a/assignment5/Question5/ManyVehicles.java b/assignment5/Question5/ManyVehicles.java
index 316e9d6..c187400 100644
--- a/assignment5/Question5/ManyVehicles.java
+++ b/assignment5/Question5/ManyVehicles.java
@@ -31,7 +31,7 @@ public class ManyVehicles {
 	 *
 	 * @return the average speed of all vehicles
 	 */
-	public double averageSpeed() {
+	public double calcAvgSpeed() {
 		double totalSpeed = 0;
 		for (Vehicle v : vehicles) {
 			totalSpeed += v.getSpeed();
@@ -50,7 +50,7 @@ public class ManyVehicles {
 			mv.addVehicle(new Aircraft(100, 70, 3900));
 			mv.addVehicle(new Train(100, 60));
 
-			System.out.println(mv.averageSpeed() == 80.0);
+			System.out.println(mv.calcAvgSpeed() == 80.0);
 		} catch (Exception e) {
 			System.out.println("Error uncaught exception: " + e.getClass().getName() + e.getMessage());
 		}
diff --git a/assignment5/Question5/StartGrading.java b/assignment5/Question5/StartGrading.java
index 563f361..a4ce63c 100644
--- a/assignment5/Question5/StartGrading.java
+++ b/assignment5/Question5/StartGrading.java
@@ -1,3 +1,4 @@
+//Q5
 public class StartGrading {
 	public static void testVehicle() {
 //The Vehicle class is abstract. We cannot create objects from this class. Therefore, we cannot test anything
@@ -6,30 +7,29 @@ public class StartGrading {
 	public static void testCar() {
 		// test case for constructors
 		try {
-// exception
+			// exception
 			Car c1 = new Car(70, 80);
 		} catch (BadSpeedSetting e) {
 			System.out.println(e.getMessage().equals("Speed cannot be greater than speed limit!"));
 		}
 		try {
-// exception
+			// exception
 			Car c2 = new Car(70, -10);
 		} catch (BadSpeedSetting e) {
 			System.out.println(e.getMessage().equals("Speed cannot be negative!"));
 		}
-// test case for accelerate, canFly and getSpeed methods
+		// test case for accelerate, canFly and getSpeed methods
 		try {
 			Car c3 = new Car(100, 80);
-// test the canFly method
+			// test the canFly method
 			System.out.println(c3.canFly() == false);
 			c3.accelerate(10);
 			System.out.println(c3.getSpeed() == 90);
-// test the accelerate with positive amount
+			// test the accelerate with positive amount
 			c3.accelerate(-20);
 			System.out.println(c3.getSpeed() == 70);
-// test the accelerate with negative amount 
-			c3.accelerate(35);
-// exception 
+			// test the accelerate with negative amount
+			c3.accelerate(35); // exception
 		} catch (BadSpeedSetting e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		} catch (ExceedSpeedLimit e) {
@@ -37,10 +37,12 @@ public class StartGrading {
 					.println(e.getMessage().equals("Current speed is 70. Accelerate 35 will exceed the speed limit!"));
 		} catch (NotEnoughSpeed e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
+		} catch (TrainSpeedChange e) {
+			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		}
 		try {
 			Car c4 = new Car(100, 80);
-// exception
+			// exception
 			c4.accelerate(-90);
 		} catch (BadSpeedSetting e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
@@ -48,6 +50,8 @@ public class StartGrading {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		} catch (NotEnoughSpeed e) {
 			System.out.println(e.getMessage().equals("Current speed is " + 80 + ", not enough speed to decelerate!"));
+		} catch (TrainSpeedChange e) {
+			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		}
 	}
 
@@ -101,6 +105,8 @@ public class StartGrading {
 					e.getMessage().equals("Current speed is 100. Accelerate 650 will exceed the speed limit!"));
 		} catch (NotEnoughSpeed e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
+		} catch (TrainSpeedChange e) {
+			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		}
 		try {
 			Aircraft a5 = new Aircraft(700, 200, 100);
@@ -114,6 +120,8 @@ public class StartGrading {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		} catch (NotEnoughSpeed e) {
 			System.out.println(e.getMessage().equals("Current speed is " + 200 + ", not enough speed to decelerate!"));
+		} catch (TrainSpeedChange e) {
+			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		}
 	}
 
@@ -123,7 +131,7 @@ public class StartGrading {
 			// exception
 			Train t1 = new Train(350, 400);
 		} catch (BadSpeedSetting e) {
-			System.out.println(e.getMessage().equals("Speed cannot be greater than	speed limit!"));
+			System.out.println(e.getMessage().equals("Speed cannot be greater than speed limit!"));
 		}
 		try {
 			// exception
@@ -149,7 +157,7 @@ public class StartGrading {
 
 	public static void testManyVehicles() {
 		ManyVehicles mv = new ManyVehicles();
-		// Add any kind of vehicles to the arraylist.
+// Add any kind of vehicles to the arraylist.
 		try {
 			Train t = new Train(350, 300);
 			mv.addVehicle(t);
@@ -163,7 +171,7 @@ public class StartGrading {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
 		}
 		try {
-			AirCraft a = new AirCraft(700, 200, 100);
+			Aircraft a = new Aircraft(700, 200, 100);
 			mv.addVehicle(a);
 		} catch (BadSpeedSetting e) {
 			System.out.println("BUG! THIS MUST NEVER HAPPEN!");
@@ -176,8 +184,7 @@ public class StartGrading {
 	public static void main(String[] args) {
 		Vehicle.testVehicle();
 		Car.testCar();
-		AirCraft.testAirCraft();
+		Aircraft.testAircraft();
 		Train.testTrain();
-		ManyVehicles.testVehicles();
 	}
 }