Update solver_router.py

solver_router.py

@@ -14,7 +14,7 @@ from solver_probability import solve_probability
 from solver_ratio import solve_ratio
 from solver_remainder import solve_remainder
 from solver_standard_deviation import solve_standard_deviation
-from solver_weighted_average_and_mixture import solve_weighted_average_and_mixture
+from solver_weighted_average import solve_weighted_average
 from solver_work_rate import solve_work_rate