finished

src/main/java/rocks/zipcode/quiz5/objectorientation/account/BankAccount.java

  * @author leon on 27/12/2018.
  */
 public class BankAccount extends Account implements Transactable {
+    private Double balance;
+
+    public BankAccount() {
+        this.balance = 0D;
+    }
+
     public void setBalance(Double val) {
+        this.balance = val;
     }
 
     @Override
     public void deposit(Double amountToIncreaseBy) {
-
+        if (amountToIncreaseBy < 0) throw new IllegalArgumentException("try again fool");
+        balance += amountToIncreaseBy;
     }
 
     @Override
     public void withdrawal(Double amountToDecreaseBy) {
-
+        if (amountToDecreaseBy < 0 || (balance - amountToDecreaseBy) < 0) throw new IllegalArgumentException("try again fool");
+        balance -= amountToDecreaseBy;
     }
 
     @Override
     public Double getBalance() {
-        return null;
+        return balance;
     }
 }

src/main/java/rocks/zipcode/quiz5/objectorientation/account/Employee.java

  * @author leon on 30/12/2018.
  */
 public class Employee implements Worker, Transactable {
+    private BankAccount bankAccount;
+    private Double hoursWorked;
+    private Double hourlyWage;
+
     public Employee() {
+        this.bankAccount = new BankAccount();
+        this.hoursWorked = 0D;
+        this.hourlyWage = 35D;
     }
 
     public Employee(BankAccount bankAccount) {
+        this();
+        this.bankAccount = bankAccount;
     }
 
     public BankAccount getBankAccount() {
-        return null;
+        return bankAccount;
     }
 
     public void setBankAccount(BankAccount bankAccount) {
-
+        this.bankAccount = bankAccount;
     }
 
     @Override
     public void increaseHoursWorked(Double numberOfHours) {
-
+        this.hoursWorked += numberOfHours;
     }
 
     @Override
     public Double getHoursWorked() {
-        return null;
+        return hoursWorked;
     }
 
     @Override
     public Double getHourlyWage() {
-        return null;
+        return hourlyWage;
     }
 
     @Override
     public Double getMoneyEarned() {
-        return null;
+        return hoursWorked*hourlyWage;
     }
 
     @Override
     public void deposit(Double amountToIncreaseBy) {
-
+        bankAccount.deposit(amountToIncreaseBy);
     }
 
     @Override
     public void withdrawal(Double amountToDecreaseBy) {
-
+        bankAccount.withdrawal(amountToDecreaseBy);
     }
 
     @Override
     public Double getBalance() {
-        return null;
+        return bankAccount.getBalance();
     }
 }