Directions: Each of the questions given below is followed by series of options among which you have to choose the best one. You can also review your choices by clicking into answer section.
16.Trains having length of 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions (on parallel tracks). The time which they take to cross each other, is
A. 10.8 s
B. 12 s
C. 9.8 s
D. 8 s
Answer
Explanation:
Distance = 140+160 = 300 m
Relative speed = 60+40 = 100 km/hr = (100×10)/36 m/s
Time = distance/speed = 300 / (100×10)/36
= 300×36 / 1000
= 3×36/10
= 10.8 s
17. Two trains A and B travel at speeds of 80kmph and 120kmph respectively, from station C to D. If train B reaches half an hour before train A, find the distance between stations C and D.
A. 150 km
B. 120 km
C. 100 km
D. 80 km
Answer
Explanation:
Let the distance between C and D be x km.
Time taken by train A = x/80,
Time taken by train B = x/120
x/80 = (x/120) + (1/2) x
= 120km
18. A goods train runs at the speed of 72 kmph and crosses a 250 m long platform in 26 seconds. What is the length of the goods train?
A. 230 m
B. 240 m
C. 260 m
D. 270 m
Answer
Explanation:
Speed =[ 72 x(5/18) ]m/sec= 20 m/sec.
Time = 26 sec.
Let the length of the train be x metres.
Then, [ (x+250)/26 ]= 20
=> x + 250 = 520
=> x = 270.
19. A jogger is running at 9 kmph alongside a railway track in 240 meters ahead of the engine of a 120 meters long train. The train is running at 45 kmph in the same direction. How much time does it take for the train to pass the jogger?
A. 46
B. 36
C. 18
D. 22
Answer
Explanation:
Distance to be covered = 240+ 120 = 360 m
Relative speed = 36 km/hr = 36 × 1000/3600 = 10 m/s
Time = distance/speed = 360/10 = 36 seconds
20. A train overtakes two persons walking at speeds of 3 kmph and 5 kmph in 14 seconds and 14.4 seconds respectively. If they are walking in the same direction as the train, find the speed of the train.
A. 72 kmph
B. 78 kmph
C. 80 kmph
D. 75 kmph
Answer
Explanation:
Let the speed of the train be x km/hr.
Relative speed of the train and the first person
= x-3 kmph = (x-3)*(5/18) m/s
Relative speed of the train and the second person
= (x-5)*(5/18) m/s
Length of the train = Relative speed*Time to overtake
[(x-3)*(5/18)]*14 = [(x-5)*(5/18)]*14.4
(x-3)*14 = (x-5)*14.4
Solving, 14x-42 = 14.4x-72
0.4x = 30
x = 75 kmph
21. Find the time taken by a train of length 200 m travelling at a speed of 90 kmph to cross a 1 km long tunnel.
A. 1 minute
B. 54 seconds
C. 48 seconds
D. 45 seconds
Answer
Explanation:
Speed of the train = 90*5/18 = 25 m/s
Time to cross the tunnel = (1000+200)/25 = 48s
22. Two trains 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other, is:
A. 9
B. 9.6
C. 10
D. 10.8
Answer
Explanation:
Relative speed = (60 + 40)km/hr= 100 x (5 /18) =250/9 m/sec.
Distance covered in crossing each other = (140 + 160) m = 300 m.
Required time = (300 x9 seC./250=54/5 sec = 10.8 sec.
23. If a train travels from station A to B at an average speed of 50 kmph without any stoppages, it reaches 5 minutes before the scheduled time. However, if it travels at an average speed of 48 kmph, it reaches 5 mins late. Find the distance between A and B.
A. 250 km
B. 200 km
C. 100 km
D. 33 km
Answer
Explanation:
Let the distance between the A and B be x km and the usual time of travel be y hours.
If speed=50 kmph, time taken = y+5 mins
(x/50) = y-(5/60)……..(i)
If speed=48 kmph, time taken = y+5 mins
(x/48) = y+(5/60)…….(ii)
Solving the two equations, x=200 km
31. How many seconds will a 500 meter long train moving with a speed of 63 km/hr, take to cross a man walking with a speed of 3 km/hr in the direction of the train?
A. 42
B. 50
C. 30
D. 28
Answer
Explanation:
Distance = 500m
Speed = 63 -3 km/hr = 60 km/hr = 600/36 m/s = 50/3 m/s
Time taken = distance/speed = 500/(50/3) = 30 s
32. A train running at the speed of 60 km/hr crosses a pole in 9 seconds. What is the length of the train?
A.120 metres
B.180 metres
C.324 metres
D.150 metres
Answer
Explanation:
Speed= (60 x5) /18 m/sec=50/3 m/sec.
Length of the train = (Speed x Time) =(50×9)/3m = 150 m.
