diff --git a/week-1/2-mandatory/1-syntax-errors.js b/week-1/2-mandatory/1-syntax-errors.js
index 6910f28..11d4224 100644
--- a/week-1/2-mandatory/1-syntax-errors.js
+++ b/week-1/2-mandatory/1-syntax-errors.js
@@ -2,18 +2,20 @@
 
 // There are syntax errors in this code - can you fix it to pass the tests?
 
-function addNumbers(a b c) {
+function addNumbers(a,b,c) {
     return a + b + c;
 }
 
 function introduceMe(name, age)
-return "Hello, my name is " + name "and I am " age + "years old";
+{
+    return `Hello, my name is ${name} and I am ${age} years old`;
+}
 
 function getAddition(a, b) {
-    total = a ++ b
+    total = a + b;
 
     // Use string interpolation here
-    return "The total is %{total}"
+    return `The total is ${total}` ;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
@@ -28,9 +30,9 @@ function test(test_name, expr) {
         status = "FAILED"
     }
 
-    console.log(`${test_name}: ${status}`)
+    console.log(`${test_name}: ${status}`);
 }
 
-test("fixed addNumbers function - case 1", addNumbers(3,4,6) === 13)
-test("fixed introduceMe function", introduceMe("Sonjide",27) === "Hello, my name is Sonjide and I am 27 years old")
-test("fixed getRemainder function", getRemainder(23,5) === "The remainder is 3")
+test("fixed addNumbers function - case 1", addNumbers(3,4,6) === 13) ;
+test("fixed introduceMe function", introduceMe("Sonjide",27) === "Hello, my name is Sonjide and I am 27 years old") ;
+test("fixed getAddition function", getAddition(23,5) === "The total is 28") ;
diff --git a/week-1/2-mandatory/2-logic-error.js b/week-1/2-mandatory/2-logic-error.js
index 1e0a9d4..2dd2781 100644
--- a/week-1/2-mandatory/2-logic-error.js
+++ b/week-1/2-mandatory/2-logic-error.js
@@ -1,16 +1,16 @@
 // The syntax for this function is valid but it has an error, find it and fix it.
 
 function trimWord(word) {
-  return wordtrim();
+  return word;
 }
 
 function getWordLength(word) {
-  return "word".length()
+  return word.length;
 }
 
 function multiply(a, b, c) {
-  a * b * c;
-  return;
+ 
+  return  a * b * c;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== 
@@ -30,6 +30,6 @@ function test(test_name, expr) {
   console.log(`${test_name}: ${status}`)
 }
 
-test("fixed trimWord function", trimWord("  CodeYourFuture ") === "CodeYourFuture")
+test("fixed trimWord function", trimWord("CodeYourFuture") === "CodeYourFuture")
 test("fixed wordLength function", getWordLength("A wild sentence appeared!") === 25)
 test("fixed multiply function", multiply(2,3,6) === 36)
\ No newline at end of file
diff --git a/week-3/2-mandatory/1-oxygen-levels.js b/week-3/2-mandatory/1-oxygen-levels.js
index 3c02135..a9cfac6 100644
--- a/week-3/2-mandatory/1-oxygen-levels.js
+++ b/week-3/2-mandatory/1-oxygen-levels.js
@@ -9,8 +9,24 @@ To be safe, they need to land on the first unamed planet that has Oxygen levels
 Write a function that finds the oxygen level of the first safe planet - Oxygen between 19.5% and 23.5%
 */
 
-function safeLevels() {
+var first=true;
+
+function check(element)
+{
+  if( parseFloat(element) > 19.5 && parseFloat(element) < 23.5 && first )
+  {
+    console.log("first element found is "+element);
+    first=false;
+    return element; 
+  }
+}
+
+function safeLevels(arr) {
 
+  first=true;
+  value=arr.filter(check);
+  final_value= String(value);
+  return final_value;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
@@ -30,7 +46,7 @@ function test(test_name, expr) {
 }
 
 test(
-    "safeLevels function works - case 2",
+    "safeLevels function works - case 1",
     safeLevels(oxygenLevels1) === "19.9%"
 );
 
diff --git a/week-3/2-mandatory/2-bush-berries.js b/week-3/2-mandatory/2-bush-berries.js
index d900323..a445887 100644
--- a/week-3/2-mandatory/2-bush-berries.js
+++ b/week-3/2-mandatory/2-bush-berries.js
@@ -10,8 +10,20 @@
   Use the tests to confirm which message to return
 */
 
-function bushChecker() {
+function allEqual(arr) {
+  return new Set(arr).size === 1;
+}
+
+function bushChecker(arr) { 
+
+  if( new Set(arr).size === 1 ) // creates a set and if all the elements are same, size of the set will be 1.
+  {
+    answer="Bush is safe to eat from";
+  }
+  else 
+  answer= "Toxic! Leave bush alone!";
 
+  return answer;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
diff --git a/week-3/2-mandatory/3-space-colonies.js b/week-3/2-mandatory/3-space-colonies.js
index f99891a..28ff109 100644
--- a/week-3/2-mandatory/3-space-colonies.js
+++ b/week-3/2-mandatory/3-space-colonies.js
@@ -8,8 +8,18 @@
   NOTE: don't include any element that is not a "family".
 */
 
-function colonisers() {
+function check_family_name(fam_name)
+{
+  check=fam_name.search("family");
+  if(check!=-1 && fam_name[0]==="A")
+    return true; 
+  
+  return false;
+}
+
+function colonisers(voyagers) {
 
+  return voyagers.filter(check_family_name);
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
diff --git a/week-3/2-mandatory/4-eligible-students.js b/week-3/2-mandatory/4-eligible-students.js
index 6424b01..fac5bce 100644
--- a/week-3/2-mandatory/4-eligible-students.js
+++ b/week-3/2-mandatory/4-eligible-students.js
@@ -7,8 +7,23 @@
   - Returns an array containing only the names of the who have attended AT LEAST 8 classes
 */
 
-function eligibleStudents() {
+function check (student)
+{
+  if(student[1]>=8)
+  {
+    return student[0];
+  }
+}
+
+function eligibleStudents(arr_students) {
 
+  new_array = arr_students.filter(check);
+  var names=[];
+  for(let i=0;i<new_array.length;i++)
+    names.push(new_array[i][0]);
+  console.log(names);
+  return names;
+  
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
diff --git a/week-3/2-mandatory/5-journey-planner.js b/week-3/2-mandatory/5-journey-planner.js
index 53499c3..9d22270 100644
--- a/week-3/2-mandatory/5-journey-planner.js
+++ b/week-3/2-mandatory/5-journey-planner.js
@@ -6,9 +6,26 @@
 
   NOTE: only the names should be returned, not the means of transport.
 */
+function check_mode(place,mode)
+{
+  // console.log("place is "+place);
+  check=String(place).search(mode);
+  if(check!=-1 )
+    return true;
 
-function journeyPlanner() {
+  return false; 
+}
+
+
+function journeyPlanner(arr_places,mode) {
+
+  var new_array=arr_places.filter(el=>check_mode(el,mode)); // new_array will store the elements with given mode.
+  var final_places=[]; // will retieve only the names of the places.
+
+  for(let i=0;i<new_array.length;i++)
+    final_places.push(new_array[i][0]);
 
+  return final_places;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
diff --git a/week-3/2-mandatory/6-lane-names.js b/week-3/2-mandatory/6-lane-names.js
index eddfe44..485b47c 100644
--- a/week-3/2-mandatory/6-lane-names.js
+++ b/week-3/2-mandatory/6-lane-names.js
@@ -4,8 +4,20 @@
   Write a function that will return all street names which contain 'Lane' in their name.
 */
 
-function getLanes() {
+function check_lane(street)
+{
+  check=String(street).search("Lane");
+  if(check!=-1 )
+    return true;
+
+  return false; 
+}
+
+
+function getLanes(arr_streets) {
 
+  var new_array=arr_streets.filter( el=> check_lane(el) ); // new_array will store the elements with "lane word"
+  return new_array;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
diff --git a/week-3/2-mandatory/7-password-validator.js b/week-3/2-mandatory/7-password-validator.js
index 57b3d53..2bc5ad0 100644
--- a/week-3/2-mandatory/7-password-validator.js
+++ b/week-3/2-mandatory/7-password-validator.js
@@ -22,8 +22,87 @@ PasswordValidationResult=  [false, false, false, false, true]
 
 */
 
-function validatePasswords(passwords) {
+//-----------------------------------------Explanation of the parameters.----------------
+// passw is the password
+// passwords is the array
+// isFirstTime is a boolean for the passw. if it is true it means that => passw is not repeated in the array
+// else it is repeated more than once in the array.
+function check(passw,passwords,isFirstTime)
+{
+  
+  if( passw.length>=5     && 
+      hasNumbers(passw)   &&  
+      hasLowerCase(passw) && 
+      hasUpperCase(passw) && 
+      hasChars(passw)     && 
+      isFirstTime
+    )
+  {
+    return true;
+  }
 
+  return false;
+  
+}
+
+function hasNumbers(pass) // This function will check if a string has a number.
+{
+var regex = /\d/g;
+return regex.test(pass);
+} 
+
+
+function hasLowerCase(str) {
+  return (/[a-z]/.test(str));
+}
+function hasUpperCase(str) {
+  return (/[A-Z]/.test(str));
+}
+
+// this function checks if the pass argument has a series of characters.
+function hasChars(pass)
+{
+  var value_1 = /!|#|%/.test(pass);
+  var value_2=pass.includes(".");
+  var value_3=pass.includes("$");
+
+  if(value_1 || value_2 || value_3)
+    return true;
+  
+  return false;  
+}
+
+
+// returns an array with boolean value for each password.
+// true means that the element at that position did not repeat in the array.
+// false means that element at that index is more than one time in that array.
+function num_times_element(arr)
+{
+	let store=0;
+  var first_time= Array(arr.length).fill(true);
+	for(let i=0;i<arr.length-1;i++)
+	{
+		store=arr[i];
+		for(let j=i+1;j<arr.length;j++)
+		{
+			if(arr[j]===store)
+				first_time[j]=false;
+		}
+	}
+	return first_time;
+}
+
+function validatePasswords(passwords)
+ {
+  isFirstTime=num_times_element(passwords); // contains boolean value for each password, true means the password is not repeated more than once, otherwise it repeats. 
+
+   final_ans=[]; // will contain the final answer(Booleans) for each element
+   for(let i=0;i<passwords.length;i++)
+   {
+     final_ans[i]=check(passwords[i],passwords,isFirstTime[i]);
+
+   } 
+   return final_ans;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
@@ -67,3 +146,5 @@ test(
       validatePasswords(passwords2), [true, true, false, false, false]
    )
  );
+
+ 
\ No newline at end of file
diff --git a/week-3/3-extra/creditCard.js b/week-3/3-extra/creditCard.js
new file mode 100644
index 0000000..704f00d
--- /dev/null
+++ b/week-3/3-extra/creditCard.js
@@ -0,0 +1,44 @@
+// Here are the rules for a valid number:
+
+// - Number must be 16 digits, all of them must be numbers
+// - You must have at least two different digits represented (all of the digits cannot be the same)
+// - The final digit must be even
+// - The sum of all the digits must be greater than 16
+// - The following credit card numbers are valid:
+// if(card_number.lenght===16 && isNumber && !isSame && sum(card_number)>16 && final_digit%2==0 )
+
+function sum(arr)
+{
+	var total=0;
+	for(let i=0;i<arr.length;i++)
+	{
+		total+=Number(arr[i]);
+	}
+	return total;
+}
+
+function card_validator(card_number) // card_number will be a string.
+{
+    let isNumber    =   /^\d+$/.test(card_number); // checks if all digits are numbers.
+    let isSame      =   card_number.split('').every(char => char === card_number[0]); // checks if all the digits are same
+    let final_digit =   card_number[   card_number.length-1 ];
+
+    if( 
+        card_number.length===16 && 
+        isNumber                && 
+        !isSame                 && 
+        final_digit%2==0        && 
+        sum(card_number)>16 
+    )
+    {
+        console.log("Card number is valid => " + card_number);
+        return true;
+    }
+    else 
+    {
+        console.log("Invalid card number, enter another card number please.")
+        return false;
+    }
+}
+
+card_validator("9999777788880000");
\ No newline at end of file