Total distance covered = 10 × 18 = 180 km Let the time to cover distance by walk be x hour So, The time to cover distance by auto = (10 - x) hr According to the question 10x + 30(10 - x) = 180 ⇒ 10x - 30x + 300 = 180 ⇒ -20x = -120 ⇒ x = 6 hrs So time taken to cover distance by auto = 10 - 6 = 4 hrs Distance traveled by auto = 30 × 4 = 120 km