320 km distance is to be covered partially by bus and partially by train. Bus overs 180 km distance with a speed of 40 km/h and the rest of the distance is covered by the train at a speed of 70 km/h. Find the time taken by a passenger to cover the whole distance.

Total distance = 320 km

Distance covered by the bus = 180 km

Speed of the bus = 40 km/h

∴ Time taken by the bus = Distance / Speed = 180 / 40 hours = 9/2 hours

Distance covered by the train = 320 - 180 = 140 km

Speed of the train = 70 km/h

∴ Time taken by the train = Distance / Speed = 140 / 70 hours = 2 hours

Hence, total time taken by the passenger 

= 9/2 hours + 2 hours 

= 4 hours 30 min + 2 hours 

= 6 hours 30 min