During its journey, a bus travels at a speed of 50 km/hr for 60 km, at 60 km/hr for 80 km and at 75 km/hr for 30 km. If the bus travelled at a constant speed of 60 km/hr, it would reach its destination?
1). 6 min. early
2). 4 min. early
3). In the same time
4). 4 min. late
⇒ Total distance travelled = 60 + 80 + 30 = 170 km
? Time = Distance/Speed
Total time taken by bus = 60/50 + 80/60 + 30/75 = 6/5 + 4/3 + 2/5 = 44/15 = 2.93 hours
When the speed of bus is 60 km/hr,
Time taken by bus = 170/60 = 17/6 = 2.83 hours
∴ The bus will reach its destination = (2.93 - 2.83) = 0.1 hrs = 0.1 × 60 = 6 min early