diff --git a/exercises/bowling/example.rs b/exercises/bowling/example.rs
index 089ef3dcb..547c4b9ce 100644
--- a/exercises/bowling/example.rs
+++ b/exercises/bowling/example.rs
@@ -104,7 +104,7 @@ impl BowlingGame {
                 return Err("Game Finished. No more rolls.");
             }
 
-            for mut frame in self.frames.iter_mut() {
+            for frame in self.frames.iter_mut() {
                 frame.add_roll(pins)
             }
 
diff --git a/exercises/grade-school/example.rs b/exercises/grade-school/example.rs
index 58f9e1e51..3b2cc7910 100644
--- a/exercises/grade-school/example.rs
+++ b/exercises/grade-school/example.rs
@@ -10,7 +10,7 @@ impl School {
     }
 
     pub fn add(&mut self, grade: u32, student: &str) {
-        let mut entry = self.grades.entry(grade).or_insert(Vec::new());
+        let entry = self.grades.entry(grade).or_insert(Vec::new());
         entry.push(student.to_string());
         entry.sort();
     }