Distance covered in first part = 400/2 = 200 km Time taken in first part = 200/50 = 4 hrs Distance covered in second part = 60% of (400 – 200) = 0.6 × 200 = 120 km Time taken in second part = 120/60 = 2 hrs Distance covered in last part = 400 – 200 – 120 = 80 km Time taken in last part = 80/80 = 1 hr ∴ Total time taken by bus to reach its destination = 4 + 2 + 1 = 7 hrs