diff --git a/numpy_questions.py b/numpy_questions.py
index 07a10c1..be798c3 100644
--- a/numpy_questions.py
+++ b/numpy_questions.py
@@ -39,9 +39,7 @@ def max_index(X):
     """
     i = 0
     j = 0
-
-    # TODO
-
+    i, j = np.unravel_index(np.argmax(X), X.shape)
     return i, j
 
 
@@ -63,5 +61,8 @@ def wallis_product(n_terms):
         The approximation of order `n_terms` of pi using the Wallis product.
     """
     # XXX : The n_terms is an int that corresponds to the number of
-    # terms in the product. For example 10000.
-    return 0.
+    # terms in the product. For example 10000.\
+    pi = 1
+    for i in range(1, n_terms+1):
+        pi *= (4*i**2)/(4*i**2-1)
+    return pi * 2