16.
Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:
• A.
1:3
• C.
3:4
• B.
3:2
• D.
None of these
• Report
Explanation :

Let the speeds of the two trains be x m/sec and y m/sec respectively. Then,

Length of the first train = 27x metres, and length of the second train = 17y metres.

 27x + 17y x + y
= 23 27x + 17y = 23x + 23y 4x = 6y
 x y
=
 3 2

Report
 Name Email
17.
A train 110 m long passes a man, running at 6 kmph in the direction opposite to that of the train, in 6 seconds. The speed of the train is:
• A.
54 km/hr
• C.
66 km/hr
• B.
60 km/hr
• D.
72 km/hr
• Report
Explanation :

Speed of the train relative to man =
 110 6
m/sec =
 110 6
x
 18 5
km/hr = 66 km/hr.

Let the speed of the train be x kmph. Then, relative speed = (x + 6) = kmph.

x + 6 = 66  or  x = 60 kmph.

Report
 Name Email
18.
A 300 metre long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?
• A.
320 m
• C.
650 m
• B.
350 m
• D.
500 m
• Report
Explanation :

Speed =
 300 18
m/sec =
 50 3
m/sec.

Let the length of the platform be x metres

Then,
 x + 300 39
=
 50 3
3 (x + 300) = 1950 x = 350 m.

Report
 Name Email
19.
A train 280 m long, running with a speed of 63 km/hr will pass a tree in:
• A.
15 sec
• C.
18 sec
• B.
16 sec
• D.
20 sec
• Report
Explanation :

Speed =   63 x
 5 18
m/sec =
 35 2
m/sec.

Time taken =   280 x
 2 35
sec = 16 sec.

Report
 Name Email
20.
A train 125 m long passes a man, running at 5 kmph in the same direction in which the train is going, in 10 seconds. The speed of the train is:
• A.
45 km/hr
• C.
54 km/hr
• B.
50 km/hr
• D.
55 km/hr
• Report
Explanation :

Speed of the train relative to man =
 125 10
m/sec =
 25 2
m/sec.

 25 2
x
 18 5
km/hr = 45 km/hr.

Let the speed of the train be x kmph. Then, relative speed = (x � 5) kmph.

x - 5 = 45  or   x = 50 kmph.

Report
 Name Email