diff --git a/learning_python3.md b/learning_python3.md
index c43c5e8..ec064c2 100644
--- a/learning_python3.md
+++ b/learning_python3.md
@@ -1449,6 +1449,8 @@ for friend in friends:
 print("{} closes the door behind him...".format(friend.capitalize()))
 ```
 
+**TODO pizza function with multiple arguments**
+
 # Coding challenge - Cheerleader chant
 
 Can you make me a program that outputs this type of cheerleader chant?
@@ -2166,6 +2168,47 @@ for dog in all_my_dogs:
 Think of some other world objects you can create a class for and do so.
 The first one that comes to mind is vehicles but you can do anything that makes sense to you.
 
+# Coding challenge - Bus line
+
+There is a bus line with with 20 stops on it.
+At each stop there are a number of people waiting according to the table below.
+Throughout the day 4 buses will pass by and each bus has 30 seats on it.
+
+* How many people are left at each stop at the end of the day?
+* How many buses would the bus line need in order to get everybody to the terminal?
+	* What if at each stop 10% of the people on the bus get off?
+
+| bus stop          | people waiting |
+|-------------------|----------------|
+| 1                 | 6             |
+| 2                 | 5             |
+| 2                 | 3             |
+| 3                 | 10             |
+| 4                 | 14             |
+| 5                 | 3             |
+| 6                 | 5             |
+| 7                 | 7             |
+| 8                 | 4             |
+| 9                 | 12             |
+| 10                 | 14             |
+| 11                 | 9             |
+| 12                 | 2             |
+| 13                 | 1             |
+| 14                 | 5             |
+| 15                 | 12             |
+| 16                 | 4             |
+| 17                 | 3             |
+| 18                 | 8             |
+| 19                 | 12             |
+| 20                 | 1             |
+
+<details>
+  <summary>Spoiler warning</summary>
+
+**TODO**
+
+</details>
+
 ## Class inheritance
 
 Inheritance is one of the four main pillars of Object Orientated Programming.