Update solver_weighted_average.py

solver_weighted_average.py

@@ -867,4 +867,8 @@ def solve_mixture_weighted_average(text: str) -> Optional[SolverResult]:
         except Exception:
             continue
 
-    return None
+    return None
+
+
+def solve_weighted_average_and_mixture(text: str) -> Optional[SolverResult]:
+    return solve_mixture_weighted_average(text)