diff --git a/src/challenge.ts b/src/challenge.ts
index fad2280..23dc7af 100644
--- a/src/challenge.ts
+++ b/src/challenge.ts
@@ -19,8 +19,7 @@ import { Student } from "./students";
  */
 function getStudentsByCourse(students: Student[], course: string): Student[] {
   // write your code here...
-
-  return []; // replace empty array with what you see is fit
+  return students.filter((student) => student.courses.includes(course)); // replace empty array with what you see is fit
 }
 
 /**
@@ -36,8 +35,15 @@ function getStudentsByCourse(students: Student[], course: string): Student[] {
  */
 function listAllCourses(students: Student[]): string[] {
   // write your code here...
-
-  return []; // replace empty array with what you see is fit
+  const coursesArray: string[] = [];
+  students.forEach((student) =>
+    student.courses.forEach((course) => {
+      if (!coursesArray.includes(course)) {
+        coursesArray.push(course);
+      }
+    })
+  );
+  return coursesArray; // replace empty array with what you see is fit
 }
 
 export { getStudentsByCourse, listAllCourses };
diff --git a/src/students.ts b/src/students.ts
index ac9d6c0..8703423 100644
--- a/src/students.ts
+++ b/src/students.ts
@@ -71,8 +71,7 @@ const students: Student[] = [
  */
 function getStudentName(student: Student): string {
   // write your code here...
-
-  return ""; // replace empty string with what you see is fit
+  return student.name; // replace empty string with what you see is fit
 }
 
 /**
@@ -86,8 +85,7 @@ function getStudentName(student: Student): string {
  */
 function getCourse(student: Student, courseIndex: number): string {
   // write your code here...
-
-  return ""; // replace empty string with what you see is fit
+  return student.courses[courseIndex]; // replace empty string with what you see is fit
 }
 
 /**
@@ -103,7 +101,7 @@ function getCourse(student: Student, courseIndex: number): string {
  */
 function addCourseToStudent(student: Student, course: string): Student {
   // write your code here...
-
+  student.courses.push(course);
   return student;
 }
 
@@ -116,8 +114,7 @@ function addCourseToStudent(student: Student, course: string): Student {
  */
 function countCourses(student: Student): number {
   // write your code here...
-
-  return -1; // replace -1 with what you see is fit
+  return student.courses.length; // replace -1 with what you see is fit
 }
 
 /**
@@ -132,9 +129,10 @@ function countCourses(student: Student): number {
  *    // => { id: 7, name: "Grace", courses: ["Math", "English", "Music"] }
  */
 function removeCourseFromStudent(student: Student, course: string): Student {
-  // write your code here...
-
-  return student;
+  return {
+    ...student,
+    courses: student.courses.filter((subject) => subject !== course),
+  };
 }
 
 /**
@@ -155,8 +153,7 @@ function findStudentById(
   studentId: number
 ): Student | undefined {
   // write your code here...
-
-  return undefined; // replace undefined with what you see is fit
+  return students.find((student) => student.id === studentId); // replace undefined with what you see is fit
 }
 
 export {