diff --git a/algorithms/oop.md b/algorithms/oop.md
index 54c32a4c..87afa145 100644
--- a/algorithms/oop.md
+++ b/algorithms/oop.md
@@ -2,3 +2,7 @@ Object-Oriented Programming
 ==
 
 - How would you design a chess game? What classes and objects would you use? What methods would they have?
+- How would you design the data structures for a book keeping system for a library?
+- Explain how you would design a http server? give examples of classes, methods, and interfaces. What are the challenging problems here?
+- Discuss algorithms and data structures for a garbage collector?
+-How would you implement an HR system to keep track of employee salaries and benefits?
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