diff --git a/exercises/02_basic_calculator/04_panics/src/lib.rs b/exercises/02_basic_calculator/04_panics/src/lib.rs
index 341a5ef..b76c565 100644
--- a/exercises/02_basic_calculator/04_panics/src/lib.rs
+++ b/exercises/02_basic_calculator/04_panics/src/lib.rs
@@ -2,7 +2,9 @@
 /// calculate the average speed of the journey.
 fn speed(start: u32, end: u32, time_elapsed: u32) -> u32 {
     // TODO: Panic with a custom message if `time_elapsed` is 0
-
+    if time_elapsed == 0 {
+        panic!("The journey took no time at all, that's impossible!");
+    }
     (end - start) / time_elapsed
 }