diff --git a/TestDotNetVrSystem/Task1.cs b/TestDotNetVrSystem/Task1.cs
index 29e6e56..b4747f7 100644
--- a/TestDotNetVrSystem/Task1.cs
+++ b/TestDotNetVrSystem/Task1.cs
@@ -8,7 +8,14 @@ public class Task1
          * Dada a lista de inteiros, retorne o maior número da lista         
          */
         public static int? GetMax(List<int> list)
-        {
+        {   int max = 0;
+            int i;
+
+            for (i = 0; i < list.Count; i++) {
+              if(max < list[i]) max = list[i]; 
+            }
+            
+            return max;
         }
     }
 }
diff --git a/TestDotNetVrSystem/Task2.cs b/TestDotNetVrSystem/Task2.cs
index 9c4fd22..157f59b 100644
--- a/TestDotNetVrSystem/Task2.cs
+++ b/TestDotNetVrSystem/Task2.cs
@@ -1,4 +1,6 @@
-namespace TestDotNetVrSystem
+
+using System;
+namespace TestDotNetVrSystem
 {
     public class Task2
     {
@@ -21,6 +23,23 @@ public class Task2
          */
         public static bool CheckInput(string input)
         {
+            int i;
+
+            if(input.Length != 7) return false;
+
+            for( i =0; i< input.Length; i++ ) {
+
+                if (i <= 2 && (Char.IsDigit(input[i])  || (Char.IsLower(input[i])))) {
+                    return false;
+                }
+
+                if (i > 2 && Char.IsLetter(input[i])) {
+                    return false;
+                }
+            }
+
+            return true;
+        
         }
     }
 }
diff --git a/TestDotNetVrSystem/Task3.cs b/TestDotNetVrSystem/Task3.cs
index d49024f..9ddea6c 100644
--- a/TestDotNetVrSystem/Task3.cs
+++ b/TestDotNetVrSystem/Task3.cs
@@ -10,6 +10,14 @@ public class Task3
          */
         public static int GetSum(List<int> list)
         {
+            int sum = 0;
+            int i;
+
+            for (i=0; i< list.Count; i++) {
+                if (list[i] > 0) sum+= list[i];
+            }
+
+            return sum;
         }
     }
 }
diff --git a/TestDotNetVrSystem/Task4.cs b/TestDotNetVrSystem/Task4.cs
index 826350e..b4171c6 100644
--- a/TestDotNetVrSystem/Task4.cs
+++ b/TestDotNetVrSystem/Task4.cs
@@ -10,6 +10,20 @@ public class Task4
          */
         public static List<Student> GetStudentsByBirth()
         {
+            Repository Repo = new Repository();
+            List <Student> studentsThisYear = new List<Student>();
+            int i;
+            int year = 2020;
+
+
+            for (i=0; i< Repo.Students.Count; i++)
+                if(Repo.Students[i].Birth.Year == year) 
+                    studentsThisYear.Add(Repo.Students[i]);
+                
+                    
+            return studentsThisYear;
+
+
         }
     }
 }
diff --git a/TestDotNetVrSystem/Task5.cs b/TestDotNetVrSystem/Task5.cs
index 8f08577..75f3c25 100644
--- a/TestDotNetVrSystem/Task5.cs
+++ b/TestDotNetVrSystem/Task5.cs
@@ -8,6 +8,15 @@ public class Task5
          */
         public static string GetEvenOrOdd(int number)
         {
+            if (number == 0) {
+                return "zero";
+            }
+            else if (number % 2 == 0) {
+                return "par";
+            }
+            else {
+                return "impar";
+            }
         }
     }
 }
diff --git a/TestDotNetVrSystem/Task6.cs b/TestDotNetVrSystem/Task6.cs
index 7fc72b1..8dcb869 100644
--- a/TestDotNetVrSystem/Task6.cs
+++ b/TestDotNetVrSystem/Task6.cs
@@ -1,5 +1,5 @@
 using System.Collections.Generic;
-
+using System;
 namespace TestDotNetVrSystem
 {
     public class Task6
@@ -17,6 +17,47 @@ public class Task6
          */
         public static List<decimal> GetRatios(List<int> numbers)
         {
+            int positiveCount = 0;
+            int negativeCount = 0;
+            int zeroCount = 0;
+
+            double positiveRatio;
+            double negativeRatio;
+            double zeroRatio;
+
+
+            List<decimal> listRatios = new List<decimal>();
+            int i;
+
+            int listLength = numbers.Count;
+
+            for (i = 0; i < listLength; i++)
+            {
+                if (numbers[i] == 0)
+                {
+                    zeroCount += 1;
+
+                }
+                else if (numbers[i] > 0)
+                {
+                    positiveCount += 1;
+                }
+                else
+                {
+                    negativeCount += 1;
+                }
+            }
+        
+            positiveRatio = (double) positiveCount / listLength;
+            negativeRatio = (double) negativeCount / listLength;
+            zeroRatio = (double) zeroCount / listLength;
+
+            listRatios.Add((decimal) Math.Round(positiveRatio, 6));
+            listRatios.Add((decimal) Math.Round(negativeRatio, 6));
+            listRatios.Add((decimal) Math.Round(zeroRatio, 6));
+
+            return listRatios;
+
         }
     }
 }
diff --git a/TestDotNetVrSystem/Task7.cs b/TestDotNetVrSystem/Task7.cs
index 601eb24..a73d099 100644
--- a/TestDotNetVrSystem/Task7.cs
+++ b/TestDotNetVrSystem/Task7.cs
@@ -1,5 +1,5 @@
 using System.Collections.Generic;
-
+using TestDotNetVrSystem.HelpClasses;
 namespace TestDotNetVrSystem
 {
     public class Task7
@@ -10,14 +10,42 @@ public class Task7
          */
         public static List<string> GetProductsOutOfStock()
         {
+            int i;
+            Repository Repo = new Repository();
+            List<string> productsOutofStock = new List<string>();
+
+
+            for (i = 0; i < Repo.Products.Count; i++)
+            {
+                if (Repo.Products[i].Stock.Quantity == 0)
+                {
+                    productsOutofStock.Add(Repo.Products[i].Name);
+                }
+            }
+
+            return productsOutofStock;
         }
 
+
+
         /*
         * Desenvolma um método que retorne a soma total das quantidades de estoque dos itens
         * Dica: A classe Repository possui as informções dos Products
         */
         public static int GetSumStock()
         {
+            int i;
+            int sumQuantity = 0;
+            Repository Repo = new Repository();
+
+
+            for (i = 0; i < Repo.Products.Count; i++)
+            {
+                sumQuantity += Repo.Products[i].Stock.Quantity;
+            }
+
+
+            return sumQuantity;
         }
 
         /*
@@ -28,6 +56,24 @@ public static int GetSumStock()
          */
         public static bool IsSalePossible(int productId, int orderQuantity)
         {
+            int i;
+            Repository Repo = new Repository();
+
+
+            for (i = 0; i < Repo.Products.Count; i++)
+            {
+                if (productId == Repo.Products[i].Id)
+                    if (Repo.Products[i].Stock.Quantity >= orderQuantity)
+                        {
+                            return true;
+                        } else
+                        {
+                            return false;
+                        }
+            }
+
+
+            return false;
         }
     }
 }