diff --git a/lectures/mccall_q.md b/lectures/mccall_q.md
index 0e8fcce6c..1be450e6e 100644
--- a/lectures/mccall_q.md
+++ b/lectures/mccall_q.md
@@ -171,7 +171,7 @@ class McCallModel:
         # Evaluate value for each state-action pair
         # Consider action = accept or reject the current offer
         accept = w[i] / (1 - β)
-        reject = c + β * np.sum(v * q)
+        reject = c + β * (v @ q)
 
         return np.array([accept, reject])