diff --git a/ch03-lists-tuples/e09b4_even_odd_sums.py b/ch03-lists-tuples/e09b4_even_odd_sums.py
index 3afc336..8a325cb 100755
--- a/ch03-lists-tuples/e09b4_even_odd_sums.py
+++ b/ch03-lists-tuples/e09b4_even_odd_sums.py
@@ -4,16 +4,7 @@
 
 def even_odd_sums(numbers):
     """Takes a list of numbers, and returns a two-element
-list containing the sum of the even elements and the
-sum of the odd elements.
+list containing the sum of the even-indexed elements and the
+sum of the odd-indexed elements.
 """
-    evens = []
-    odds = []
-
-    for one_number in numbers:
-        if one_number % 2:
-            odds.append(one_number)
-        else:
-            evens.append(one_number)
-
-    return [sum(evens), sum(odds)]
+    return [sum(numbers[0::2]), sum(numbers[1::2])]