diff --git a/education/software development/ECE1400/Chapter 15 Exercises.md b/education/software development/ECE1400/Chapter 15 Exercises.md
index f6c0577..d26c8bb 100644
--- a/education/software development/ECE1400/Chapter 15 Exercises.md	
+++ b/education/software development/ECE1400/Chapter 15 Exercises.md	
@@ -59,8 +59,8 @@ main.o: main.c f1.h
 f1.o: f1.c f1.h f2.h
 	gcc -c f1.c
 
-f2.o: f1.o f2.c f2.h
-	gcc -c f2.c f1.o
+f2.o: f2.c f2.h
+	gcc -c f2.c
 
 ```
 ---
@@ -72,11 +72,11 @@ f2.o: f1.o f2.c f2.h
 
 > (b). If `f1.c` is changed after the program has been built, which files need to be recompiled?
 
-All dependents of `f1.c` and `f1.c`, in this case `f1.c`, `main.c`, and `f2.c`.
+Just `f1.c`.
 
 > (c). If `f1.h` is changed after the program has been built, which files need to be recompiled?
 
-All source files.
+All source files, because they all include `f1.h`.
 
 > (d). If `f2.h` is changed after the program has been built, which files need to be recompiled?