diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index cd779308a..575136836 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,3 +1,14 @@
-function contains() {}
+function contains(keyInput, valueInput) {
+  if (Array.isArray(keyInput) == true) {
+    return false;
+  } else {
+    for (const key in keyInput) {
+      if (key == valueInput) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
 
 module.exports = contains;
diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index 326bdb1f2..b7180cf13 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -1,35 +1,21 @@
 const contains = require("./contains.js");
 
-/*
-Implement a function called contains that checks an object contains a
-particular property
+test("Give a contains with object and property and if the object contains the property returns true", () => {
+  expect(contains({ a: 1, b: 2 }, "b")).toEqual(true);
+});
 
-E.g. contains({a: 1, b: 2}, 'a') // returns true
-as the object contains a key of 'a'
+test("Give a contains with empty object and  when passed to contains it returns false", () => {
+  expect(contains({}, "y")).toEqual(false);
+});
 
-E.g. contains({a: 1, b: 2}, 'c') // returns false
-as the object doesn't contains a key of 'c'
-*/
+test("Give a contains with object and property and if the object contains the property returns true", () => {
+  expect(contains({ a: 1, b: 2 }, "a")).toEqual(true);
+});
 
-// Acceptance criteria:
+test("Give a contains with object and property and if the property is non-existent returns false", () => {
+  expect(contains({ a: 1, b: 2 }, "z")).toEqual(false);
+});
 
-// Given a contains function
-// When passed an object and a property name
-// Then it should return true if the object contains the property, false otherwise
-
-// Given an empty object
-// When passed to contains
-// Then it should return false
-test.todo("contains on empty object returns false");
-
-// Given an object with properties
-// When passed to contains with an existing property name
-// Then it should return true
-
-// Given an object with properties
-// When passed to contains with a non-existent property name
-// Then it should return false
-
-// Given invalid parameters like an array
-// When passed to contains
-// Then it should return false or throw an error
+test("Give invalid parameter in this case array when passed to contains it returns false", () => {
+  expect(contains(["a", 2, "b", 3, 2], 2)).toEqual(false);
+});
diff --git a/Sprint-2/implement/lookup.js b/Sprint-2/implement/lookup.js
index a6746e07f..08035feb3 100644
--- a/Sprint-2/implement/lookup.js
+++ b/Sprint-2/implement/lookup.js
@@ -1,5 +1,10 @@
-function createLookup() {
+function createLookup(countryCurrencyPairs) {
   // implementation here
+  pairs = {};
+  for (const [country, currency] of countryCurrencyPairs) {
+    pairs[country] = currency;
+  }
+  return pairs;
 }
 
 module.exports = createLookup;
diff --git a/Sprint-2/implement/lookup.test.js b/Sprint-2/implement/lookup.test.js
index 547e06c5a..d0bcef3fb 100644
--- a/Sprint-2/implement/lookup.test.js
+++ b/Sprint-2/implement/lookup.test.js
@@ -1,35 +1,16 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
-
-/*
-
-Create a lookup object of key value pairs from an array of code pairs
-
-Acceptance Criteria:
-
-Given
- - An array of arrays representing country code and currency code pairs
-   e.g. [['US', 'USD'], ['CA', 'CAD']]
-
-When
- - createLookup function is called with the country-currency array as an argument
-
-Then
- - It should return an object where:
- - The keys are the country codes
- - The values are the corresponding currency codes
-
-Example
-Given: [['US', 'USD'], ['CA', 'CAD']]
-
-When
-createLookup(countryCurrencyPairs) is called
-
-Then
-It should return:
- {
-   'US': 'USD',
-   'CA': 'CAD'
- }
-*/
+test("creates a country currency code lookup for multiple codes", () => {
+  expect([["UK", "GBP"]]).toEqual({ UK: "GBP" });
+});
+test("creates an empty  country currency code returns empty lookup  ", () => {
+  expect([]).toEqual({});
+});
+
+test("for multiple country currency returns multiple lookup", () => {
+  expect([
+    ["UK", "GBP"],
+    ["ET", "ETB"],
+    ["FR", "EUR"],
+  ]).toEqual({ UK: "GBP", ET: "ETB", FR: "EUR" });
+});
diff --git a/Sprint-2/implement/querystring.js b/Sprint-2/implement/querystring.js
index 45ec4e5f3..4c68c2243 100644
--- a/Sprint-2/implement/querystring.js
+++ b/Sprint-2/implement/querystring.js
@@ -1,13 +1,41 @@
 function parseQueryString(queryString) {
   const queryParams = {};
-  if (queryString.length === 0) {
+  if (!queryString) {
     return queryParams;
   }
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    // Skip completely empty segments from '&&' or trailing '&'
+    if (!pair) continue;
+
+    // 2. Split on '=' separating key and value
+    const eqIndex = pair.indexOf("=");
+    let rawKey, rawValue;
+
+    if (eqIndex === -1) {
+      // Key with no '=' (e.g. "key")
+      rawKey = pair;
+      rawValue = "";
+    } else {
+      rawKey = pair.slice(0, eqIndex);
+      rawValue = pair.slice(eqIndex + 1);
+    }
+
+    // 3. Replace '+' with ' ' first, then decode URL percent-encoded values
+    const key = decodeURIComponent(rawKey.replace(/\+/g, " "));
+    const value = decodeURIComponent(rawValue.replace(/\+/g, " "));
+
+    // 4. Handle identical keys (stretch goal)
+    if (queryParams.hasOwnProperty(key)) {
+      if (Array.isArray(queryParams[key])) {
+        queryParams[key].push(value);
+      } else {
+        queryParams[key] = [queryParams[key], value];
+      }
+    } else {
+      queryParams[key] = value;
+    }
   }
 
   return queryParams;
diff --git a/Sprint-2/implement/querystring.test.js b/Sprint-2/implement/querystring.test.js
index 328b8df61..a2f400262 100644
--- a/Sprint-2/implement/querystring.test.js
+++ b/Sprint-2/implement/querystring.test.js
@@ -3,7 +3,7 @@
 // Below are some test cases the implementation doesn't handle well.
 // Fix the implementation for these tests, and try to think of as many other edge cases as possible - write tests and fix those too.
 
-const parseQueryString = require("./querystring.js")
+const parseQueryString = require("./querystring.js");
 
 test("should parse values containing '='", () => {
   expect(parseQueryString("equation=a=b-2")).toEqual({
@@ -36,13 +36,3 @@ test("should replace '+' by ' '", () => {
     "full name": "John Doe",
   });
 });
-
-// Stretch exercise: Handling query strings that contain identical keys
-
-// Delete this test if you are not working on this optional case
-test("should store values of a key in an array when the key has 2 or more values", () => {
-  expect(parseQueryString("key=value1&key=value2&key=value3&foo=bar")).toEqual({
-    key: ["value1", "value2", "value3"],
-    foo: "bar",
-  });
-});
diff --git a/Sprint-2/implement/tally.js b/Sprint-2/implement/tally.js
index f47321812..f8c2dfcb8 100644
--- a/Sprint-2/implement/tally.js
+++ b/Sprint-2/implement/tally.js
@@ -1,3 +1,12 @@
-function tally() {}
+function tally(items) {
+  const result = {};
+  if (!Array.isArray(items)) {
+    throw new Error("Invalid input!");
+  }
+  for (const item of items) {
+    result[item] = (result[item] || 0) + 1;
+  }
+  return result;
+}
 
 module.exports = tally;
diff --git a/Sprint-2/implement/tally.test.js b/Sprint-2/implement/tally.test.js
index 2ceffa8dd..9b489aa3a 100644
--- a/Sprint-2/implement/tally.test.js
+++ b/Sprint-2/implement/tally.test.js
@@ -19,16 +19,25 @@ const tally = require("./tally.js");
 // Given a function called tally
 // When passed an array of items
 // Then it should return an object containing the count for each unique item
+test("given an array of items returns an object containing the counter for each item", () => {
+  expect(["a", "a"]).toEqual({ a: 2 });
+});
 
 // Given an empty array
 // When passed to tally
 // Then it should return an empty object
-test.todo("tally on an empty array returns an empty object");
-
+test("tally on an empty array returns an empty object", () => {
+  expect([]).toEqual({});
+});
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
-
+test("given an array of duplicated items returns an object containing the counter for each item", () => {
+  expect(["a", "a"]).toEqual({ a: 2 });
+});
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+test("tally on an empty array returns an empty object", () => {
+  expect(() => tally("string").toThrow("Invalid input!"));
+});