diff --git a/Algo/Courses/Chapter 6 - Lists (Exercises).md b/Algo/Courses/Chapter 6 - Lists (Exercises).md
index 8e8b692..86baea9 100644
--- a/Algo/Courses/Chapter 6 - Lists (Exercises).md	
+++ b/Algo/Courses/Chapter 6 - Lists (Exercises).md	
@@ -198,8 +198,14 @@ val insert_nth: 'a -> int -> 'a list -> 'a list = <fun>
 ```
 
 ## Exercise 3.4
-```
-# let insert_post x y list = match list with
+```Ocaml
+# let insert_post x y = function
 	| [] -> failwith "list is too large or empty"
-	| e::t -> if e = x then e::y::t else e::insert_post x y (t);;
-val insert_post : 'a -> a' list -> list = <fun>
\ No newline at end of file
+	| e::t -> if e = y then e::x::t else e::insert_post x y t;;
+val insert_post : 'a -> 'a -> a' list -> list = <fun>
+```
+
+## Exercise 3.5
+```
+
+```