diff --git a/education/software development/ECE1400/Chapter 13 Exercises.md b/education/software development/ECE1400/Chapter 13 Exercises.md
index a953771..33af519 100644
--- a/education/software development/ECE1400/Chapter 13 Exercises.md	
+++ b/education/software development/ECE1400/Chapter 13 Exercises.md	
@@ -55,6 +55,16 @@ strcat(str, "");
 
 > **9.** What will be the value of the string `s1` after the following statements have been executed?
 ```c
+// Assuming `str` is an empty string with enough space to store everything:
 strcpy(str, "tire-bouchon");
-strcpy(&str[4], "d-or-wi")
+// "tire-bouchon"
+strcpy(&str[4], "d-or-wi");
+// "tired-or-wir"
+strcat(str, "red?");
+// "tired-or-wired?"
+```
+
+Expected output:
+```c
+"tired-or-wired?"
 ```
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