diff --git a/interview.py b/interview.py
new file mode 100644
index 0000000..c496032
--- /dev/null
+++ b/interview.py
@@ -0,0 +1,34 @@
+'''
+
+Problem: Creage averager with following behavior.
+
+>>> avg(10)
+10.0
+>>> avg(11)
+10.5
+>>> avg(12)
+11.0
+
+Lead to functional implementation, explaining closures.
+
+'''
+
+# Class-based implementation
+class Averager():
+
+    def __init__(self):
+        self.series = []
+
+    def __call__(self, new_value):
+        self.series.append(new_value)
+        return sum(self.series) / len(self.series)
+
+# Functional implementation
+def make_averager():
+    series = []
+
+    def averager(new_value):
+        series.append(new_value)
+        return sum(series) / len(series)
+
+    return averager