Question

An express train takes 1 hour less than a passenger train to travel 132 km between Mysore and Bangalore .If the average speed of the express train is 11km/h more than that is f passenger train , find the average speed of the two trains.

Answer 1

An express train takes 1 hour less than a passenger train

An express train takes 1 hour less than a passenger train to travel 132 km/hr

Let the speed of passenger train be x km/hr
Hence speed of express train = (x +11) km/hr
Distance travelled by both the trains = 132 km
Time taken = (Distance)/(Speed)
Time taken by the passenger train = 132/x hrs
Time taken by the express train = 132/(x + 11) hrs

⇒�132 × 11 = x(x + 11)
⇒�x2�+ 11x – 1452 = 0
⇒�x2�+ 44x – 33x – 1452 = 0
⇒�x(x + 44) – 33(x + 44) = 0
⇒�(x + 44)(x – 33) = 0
⇒�(x + 44) = 0 or (x – 33) = 0
∴ x = –44 or x = 33
Since speed cannot be negative, x = 33
Thus the sped of passenger train is 33 km/hr and speed of express train is 44 km/hr.