diff --git a/templates/_folder_Exercises/O03/cannonball.h b/templates/_folder_Exercises/O03/cannonball.h
index 94c8782f7bf6cf51c9df7eac7e981ce09c47d836..744f4280c70441df8458fb826196fec3c64546ac 100644
--- a/templates/_folder_Exercises/O03/cannonball.h
+++ b/templates/_folder_Exercises/O03/cannonball.h
@@ -26,7 +26,7 @@ constexpr double gravity = 9.81;
 // Deklarer funksjonen flightTime
 // END: 1e
 
-int testDeviation(double compareOperand, double toOperand, double maxError, string name);
+bool testDeviation(double compareOperand, double toOperand, double maxError, string name);
 
 // Del 2:
 // BEGIN: 4a