diff --git a/24buildapi/main.go b/24buildapi/main.go
index 8853786..d392c08 100644
--- a/24buildapi/main.go
+++ b/24buildapi/main.go
@@ -64,13 +64,13 @@ func serveHome(w http.ResponseWriter, r *http.Request) {
 
 func getAllCourses(w http.ResponseWriter, r *http.Request) {
 	fmt.Println("Get all courses")
-	w.Header().Set("Content-Type", "applicatioan/json")
+	w.Header().Set("Content-Type", "application/json")
 	json.NewEncoder(w).Encode(courses)
 }
 
 func getOneCourse(w http.ResponseWriter, r *http.Request) {
 	fmt.Println("Get one course")
-	w.Header().Set("Content-Type", "applicatioan/json")
+	w.Header().Set("Content-Type", "application/json")
 
 	// grab id from request
 	params := mux.Vars(r)
@@ -88,7 +88,7 @@ func getOneCourse(w http.ResponseWriter, r *http.Request) {
 
 func createOneCourse(w http.ResponseWriter, r *http.Request) {
 	fmt.Println("Create one course")
-	w.Header().Set("Content-Type", "applicatioan/json")
+	w.Header().Set("Content-Type", "application/json")
 
 	// what if: body is empty
 	if r.Body == nil {
@@ -120,7 +120,7 @@ func createOneCourse(w http.ResponseWriter, r *http.Request) {
 
 func updateOneCourse(w http.ResponseWriter, r *http.Request) {
 	fmt.Println("Update one course")
-	w.Header().Set("Content-Type", "applicatioan/json")
+	w.Header().Set("Content-Type", "application/json")
 
 	// first - grab id from req
 	params := mux.Vars(r)
@@ -143,7 +143,7 @@ func updateOneCourse(w http.ResponseWriter, r *http.Request) {
 
 func deleteOneCourse(w http.ResponseWriter, r *http.Request) {
 	fmt.Println("Delete one course")
-	w.Header().Set("Content-Type", "applicatioan/json")
+	w.Header().Set("Content-Type", "application/json")
 
 	params := mux.Vars(r)
 
diff --git a/27mutexAndAwaitGroups/main.go b/27mutexAndAwaitGroups/main.go
index e0217ea..73c89b0 100644
--- a/27mutexAndAwaitGroups/main.go
+++ b/27mutexAndAwaitGroups/main.go
@@ -13,7 +13,7 @@ func main() {
 
 	var score = []int{0}
 
-	wg.Add(3)
+	wg.Add(4)
 	go func(wg *sync.WaitGroup, m *sync.RWMutex) {
 		fmt.Println("One R")
 		mut.Lock()
@@ -37,7 +37,7 @@ func main() {
 		wg.Done()
 	}(wg, mut)
 	go func(wg *sync.WaitGroup, m *sync.RWMutex) {
-		fmt.Println("Three R")
+		fmt.Println("Reading Scores")
 		mut.RLock()
 		fmt.Println(score)
 		mut.RUnlock()
diff --git a/28channels/main.go b/28channels/main.go
index efcb554..afc61be 100644
--- a/28channels/main.go
+++ b/28channels/main.go
@@ -17,20 +17,20 @@ func main() {
 	// R ONLY
 	go func(ch <-chan int, wg *sync.WaitGroup) {
 
-		val, isChanelOpen := <-myCh
+		val, isChanelOpen := <-ch
 
 		fmt.Println(isChanelOpen)
 		fmt.Println(val)
 
-		//fmt.Println(<-myCh)
+		//fmt.Println(<-ch)
 
 		wg.Done()
 	}(myCh, wg)
 	// send ONLY
 	go func(ch chan<- int, wg *sync.WaitGroup) {
-		myCh <- 0
-		close(myCh)
-		// myCh <- 6
+		ch <- 0
+		close(ch)
+		// ch <- 6
 		wg.Done()
 	}(myCh, wg)