# Problems on Trains - Aptitude Questions and Answers - RejinpaulPlacement

15.
How long does a train 110 metres long running at the speed of 72 km/hr take to cross a bridge 132 metres in length? [R.R.B. 1998]

Solution:   Speed of the train
= (72 * 5/18) m/sec = 20 m/sec

Total distance covered = (110 + 132) m = 242 m.

Therefore, Required time = (242/20) sec = 12.1 sec.
16.
A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long? [B.S.F. 2001]

Solution:   Speed of the train
= (45 * 5/18) m/sec
= 25/2 m/sec.

Total difference covered = (360 + 140) m = 500 m.

Therefore, Required time = (500 * 2/25) sec = 40 sec.
17.
A train travelling at a speed of 75 mph enters a tunnel 3 ½ miles long. The train is ¼ mile long. How long does it take for the train to pass through the tunnel from the moment the front enters to the moment the rear emerges?

Solution:   Total distance covered
= (7/2 + ¼) miles
= 15/4 miles.

Time taken
= ( 15/(4 * 75)) hrs
= 1/20 hrs
= [(1/20) * 60] min = 3 min.
18.
A train running at the speed of 60 km/hr crosses a pole in 9 seconds. What is the length of the train? [Bank P.O. 2003]
Solution:   Speed of the train
= [60 *( 5/18)] m/sec
= (50/3) m/sec.

Length of the train
= ( Speed * Time)
= ((50/3) * 9) m = 150 m.
19.
A train covers a distance of 12km in 10 min. If it takes 6 seconds to pass a telegraph post, then the length of the train is: [Bank P.O 2000]

Solution:   Speed of the train
= ((12/10) * 60) km/hr
=(72 * (5/18)) m/sec
= 20 m/sec

Length of the train
= (Speed * Time)
= (20 * 6) m/sec = 120 m
20.
A train covers 240 m long passed a pole in 24 seconds. How long will it take to pass a platform 650 m long? [R.R.B. 1998]

Solution:   Speed of the train
= (240/24) m/sec = 10 m/sec.

Required time = ((240 + 650) / 10) sec = 89 sec.
21.
A train 132 m long passes a telegraph pole in 6 seconds. Find the speed of the train.