diff --git a/exercises/03_ticket_v1/08_stack/src/lib.rs b/exercises/03_ticket_v1/08_stack/src/lib.rs
index e97518c..ad7d2a4 100644
--- a/exercises/03_ticket_v1/08_stack/src/lib.rs
+++ b/exercises/03_ticket_v1/08_stack/src/lib.rs
@@ -6,16 +6,16 @@ mod tests {
 
     #[test]
     fn u16_size() {
-        assert_eq!(size_of::<u16>(), todo!());
+        assert_eq!(size_of::<u16>(), 2);
     }
 
     #[test]
     fn i32_size() {
-        assert_eq!(size_of::<i32>(), todo!());
+        assert_eq!(size_of::<i32>(), 4);
     }
 
     #[test]
     fn bool_size() {
-        assert_eq!(size_of::<bool>(), todo!());
+        assert_eq!(size_of::<bool>(), 1);
     }
 }
diff --git a/exercises/03_ticket_v1/09_heap/src/lib.rs b/exercises/03_ticket_v1/09_heap/src/lib.rs
index 7273c20..89da015 100644
--- a/exercises/03_ticket_v1/09_heap/src/lib.rs
+++ b/exercises/03_ticket_v1/09_heap/src/lib.rs
@@ -13,7 +13,7 @@ mod tests {
 
     #[test]
     fn string_size() {
-        assert_eq!(size_of::<String>(), todo!());
+        assert_eq!(size_of::<String>(), 24);
     }
 
     #[test]
@@ -23,6 +23,6 @@ mod tests {
         // but, in general, the memory layout of structs is a more complex topic.
         // If you're curious, check out the "Type layout" section of The Rust Reference
         // https://doc.rust-lang.org/reference/type-layout.html for more information.
-        assert_eq!(size_of::<Ticket>(), todo!());
+        assert_eq!(size_of::<Ticket>(), 72);
     }
 }
diff --git a/exercises/03_ticket_v1/10_references_in_memory/src/lib.rs b/exercises/03_ticket_v1/10_references_in_memory/src/lib.rs
index d580758..d184a19 100644
--- a/exercises/03_ticket_v1/10_references_in_memory/src/lib.rs
+++ b/exercises/03_ticket_v1/10_references_in_memory/src/lib.rs
@@ -13,16 +13,16 @@ mod tests {
 
     #[test]
     fn u16_ref_size() {
-        assert_eq!(size_of::<&u16>(), todo!());
+        assert_eq!(size_of::<&u16>(), 8);
     }
 
     #[test]
     fn u64_mut_ref_size() {
-        assert_eq!(size_of::<&mut u64>(), todo!());
+        assert_eq!(size_of::<&mut u64>(), 8);
     }
 
     #[test]
     fn ticket_ref_size() {
-        assert_eq!(size_of::<&Ticket>(), todo!());
+        assert_eq!(size_of::<&Ticket>(), 8);
     }
 }
diff --git a/exercises/03_ticket_v1/11_destructor/src/lib.rs b/exercises/03_ticket_v1/11_destructor/src/lib.rs
index 45bc89c..6555fbb 100644
--- a/exercises/03_ticket_v1/11_destructor/src/lib.rs
+++ b/exercises/03_ticket_v1/11_destructor/src/lib.rs
@@ -2,7 +2,7 @@
 // We'll pick the concept up again in a later chapter after covering traits and
 // interior mutability.
 fn outro() -> &'static str {
-    "I have a basic understanding of __!"
+    "I have a basic understanding of destructors!"
 }
 
 #[cfg(test)]
diff --git a/exercises/03_ticket_v1/12_outro/src/lib.rs b/exercises/03_ticket_v1/12_outro/src/lib.rs
index 15c99b8..7f59a29 100644
--- a/exercises/03_ticket_v1/12_outro/src/lib.rs
+++ b/exercises/03_ticket_v1/12_outro/src/lib.rs
@@ -11,3 +11,74 @@
 // Integration here has a very specific meaning: they test **the public API** of your project.
 // You'll need to pay attention to the visibility of your types and methods; integration
 // tests can't access private or `pub(crate)` items.
+
+pub struct Order {
+    product_name: String,
+    quantity: u32,
+    unit_price: u32,
+}
+
+impl Order {
+    fn cName(name: &String) {
+        if name.is_empty() {
+            panic!("Name must be valid");
+        }
+        if name.len() > 300 {
+            panic!("Name too long");
+        }
+    }
+
+    fn cQuantity(quantity: &u32) {
+        if quantity.eq(&0) {
+            panic!("not enough quantity");
+        }
+    }
+
+    fn cPrice(price: &u32) {
+        if price.eq(&0) {
+            panic!("invalid price");
+        }
+    }
+
+    pub fn total(&self) -> u32 {
+        self.unit_price * self.quantity
+    }
+
+    pub fn new(name: String, quantity: u32, price: u32) -> Order {
+        Order::cName(&name);
+        Order::cPrice(&price);
+        Order::cQuantity(&quantity);
+        Order {
+            product_name: name,
+            quantity,
+            unit_price: price,
+        }
+    }
+
+    pub fn product_name(&self) -> String {
+        self.product_name.clone()
+    }
+
+    pub fn quantity(&self) -> &u32 {
+        &self.quantity
+    }
+
+    pub fn unit_price(&self) -> &u32 {
+        &self.unit_price
+    }
+
+    pub fn set_product_name(&mut self, name: String) {
+        Order::cName(&name);
+        self.product_name = name;
+    }
+
+    pub fn set_quantity(&mut self, quantity: u32) {
+        Order::cQuantity(&quantity);
+        self.quantity = quantity;
+    }
+
+    pub fn set_unit_price(&mut self, price: u32) {
+        Order::cPrice(&price);
+        self.unit_price = price;
+    }
+}