Important Formulas
Problems on Trains
Q1. A train moves with the speed of 180 km/hr. Find the
speed in m/sec ?
(a) 20 m/sec
(b) 30 m/sec
(c) 50 m/sec
(d) 70 m/sec
Answer: (c) 50 m/sec
180 km/hr = 180 X (5/18) = 50 m/sec
Q2. A 150 metres long train moving at the speed of 126
km/hr. What time it will take to cross an electric pole ?
(a) 3.5 seconds
(b) 4.2 seconds
(c) 5 seconds
(d) 6 seconds
Answer: (b) 4.2 seconds
126 km/hr = 126 X (5/18) = 35 m/sec
So the time taken by the train = (150/35) = 4.2 sec
Q3. A train of length 250 meter long running at the speed
of 10 m/sec. How much time it will take to cross a platform
of 650 meter length ?
(a) 60 seconds
(b) 72 seconds
(c) 85 seconds
(d) 90 seconds
Answer: (d) 90 seconds
Total length to cross the platform = 250 + 650 = 900 meter
So the time taken by the train = (900/10) = 90 sec
Q4. A train with a uniform speed crosses a pole in 2
seconds and a bridge of length 250m in 7 seconds. The length
of the train is ?
(a) 85 metre
(b) 100 metre
(c) 105 metre
(d) 125 metre
Answer: (b) 100 metre
Let the length of the train is x metre
Speed of the train is,
x/2 = (x + 250)/7
7x = 2x + 500
x = 100 metre
Q5. A train of 260 m long passed a pole in 26 secconds.
How long will it take to pass a platform of 740 m long ?
(a) 78 seconds
(b) 96 seconds
(c) 100 seconds
(d) 115 seconds
Answer: (c) 100 seconds
Speed of the train = 260/26 = 10 m /sec
So required time to cross the platform is,
=(260 + 740 )/10
=100 sec
Q6. A train travels first 160 Km at 64 Km/hr and the next 160 Km at 80 Km/hr. The average speed for the first 320 Km of the tour is
(a) 57.24 km/hr
(b) 71.11 km/hr
(c) 78.32 km/hr
(d) 91 km/hr
Answer: (b) 71.11 km/hr
Total time taken =( (160/64) + (160/80)) hrs= 9/2 hrs
Average Speed
=(320 X (2/9)) km/hr
=71.11 km/hr
Q7. The ratio between the speeds of two trains is 5 : 6. If the second train runs 600 km in 5 hours, the speed of the first train is
(a) 30 km/hr
(b) 90 km/hr
(c) 100 km/hr
(d) 300 km/hr
Answer: (c) 100 km/hr
Let the speed of the first train is 5x km/hr
Let the speed of the 2nd train is 6x km/hr
Now speed of 2nd train = 600/5 km/hr = 120 km/hr
A/Q 6x = 120
=> x = 20
∴ Speed of the 1st train = 5 X 20 = 100 km/hr
Q8. Two trains approach each other at 30 km/hr and 27 km/hr from two places 342 km apart. After how many hours will they meet ?
(a) 6 hrs
(b) 9 hrs
(c) 10 hrs
(d) 11 hrs
Answer: (a) 6 hrs
Let the two trains meet after x hours
A/Q 30x + 27x = 342
=> 57x = 342
=> x = 342/57 = 6
∴ Both the train will meet after 6 hours
Q9. The speed of a 180m long train is 60 km/hr. How much time will take to pass a platform of 600m long ?
(a) 40 sec
(b) 42.5 sec
(c) 45.8 sec
(d) 46.8 sec
Answer: (d) 46.8 sec
Speed = 60 km/hr = (6000 / (60X60)) m/sec = 50/3 m/sec
Required time = | Distance | = | 600 + 180 | sec | = | 780 X 3 | sec |
Speed | 50/3 | 50 |
= 46.8 sec
Q10. A train travelling at a speed of 30 m/sec crosses a platform 600m long in 30 seconds. The length of the train is
(a) 200m
(b) 250m
(c) 300m
(d) 450m
Answer: (c) 300m
Let the length of the train be x meter
∴ Speed of the train = (600+x)/30 m/sec
=> 30 m/sec = (600+x)/30 m/sec
=> 600 + x = 900
=> x = 900 - 600 = 300m
Practice Test Exam