Update Readme

Author: joshkil

15-challenge.c

@@ -8,7 +8,7 @@
 
 
 /*
- * Challenge 16 : Create an application to read input from the keyboard until
+ * Challenge 15 : Create an application to read input from the keyboard until
  * the user types a 'q' (quit) on a single line followed by return. Store the user's input 
  * into a dynamically allocated character array. After the user enters 'q' to quit, print 
  * statistics about the input to the screen. Print the size of input, size of storage array, 

README.md

@@ -56,7 +56,7 @@ If you want a comprehensive journey through basic programming, here is a list of
       - Challenge Solution [14-challenge.c](./14-challenge.c)
  15. [Dynamic Memory](https://youtu.be/zesiwnKVkW8)
       - Program [15-structures.c](./15-dynamic-memory.c)
-      - [15-Program Challenge Solution Explained]() 
+      - [15-Program Challenge Solution Explained](https://youtu.be/DPTuzLZuf_c) 
       - Challenge Solution [15-challenge.c](./15-challenge.c)