diff --git a/exercises/20_threads/threads1.rs b/exercises/20_threads/threads1.rs
index 4dd26c1..3db13e2 100644
--- a/exercises/20_threads/threads1.rs
+++ b/exercises/20_threads/threads1.rs
@@ -8,8 +8,6 @@
 // Execute `rustlings hint threads1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::thread;
 use std::time::{Duration, Instant};
 
diff --git a/exercises/20_threads/threads2.rs b/exercises/20_threads/threads2.rs
index 60d6824..34a7df6 100644
--- a/exercises/20_threads/threads2.rs
+++ b/exercises/20_threads/threads2.rs
@@ -7,9 +7,7 @@
 // Execute `rustlings hint threads2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::Duration;
 
@@ -19,7 +17,7 @@ struct JobStatus {
 
 fn main() {
     // TODO: `Arc` isn't enough if you want a **mutable** shared state
-    let status = Arc::new(JobStatus { jobs_completed: 0 });
+    let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));
 
     let mut handles = vec![];
     for _ in 0..10 {
@@ -27,7 +25,8 @@ fn main() {
         let handle = thread::spawn(move || {
             thread::sleep(Duration::from_millis(250));
             // TODO: You must take an action before you update a shared value
-            status_shared.jobs_completed += 1;
+            let mut s = status_shared.lock().unwrap();
+            s.jobs_completed += 1;
         });
         handles.push(handle);
     }
@@ -38,5 +37,5 @@ fn main() {
     }
 
     // TODO: Print the value of `JobStatus.jobs_completed`
-    println!("Jobs completed: {}", ???);
+    println!("Jobs completed: {}", status.lock().unwrap().jobs_completed);
 }