Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 1)
1.
A train running at the speed of 60 km/hr crosses a pole in 9 seconds. What is the length of the train?
120 metres
180 metres
324 metres
150 metres
Answer: Option
Explanation:

Speed = 60 x 5 m/sec = 50 m/sec.
18 3

Length of the train = (Speed x Time).

Length of the train = 50 x 9 m = 150 m.
3

Discussion:
584 comments Page 59 of 59.

Sundar said:   1 decade ago
Feet to Meter conversion: 1 feet = 0.3048 meter

Meter to Feet conversion: 1 meter = 3.28083 feet
(2)

Dhesappan said:   1 decade ago
Any one know the how many feet is one meter?
(2)

Karthick said:   2 decades ago
Nice explanation for beginners.
(7)

Sundar said:   2 decades ago
Why we are multiplying the 60 with 5/18?

The answer is simple. We are converting the 'kilo-meters/hour' value into 'meters/second'.

Let me explain about converting km/hr into m/s in detail.

1 km = 1000 meters.
1 hr = 3600 seconds.

1 km/hr = 1000/3600 m/s

= 10/36 m/s

= 5/18 m/s.

Therefore 1 km/hr = 5/18 m/sec.

Similarly 60 km/hr = 60 x 5/18 m/sec.

You may ask me, why should I convert it from km/hr to m/sec?

Because, the time taken by the train is given in terms of seconds (9 seconds) and the 4 options are in terms of metres. But the speed of the train is given in terms of km/hr. So we have to convert the values from km/hr to m/s in order to find the solution in terms of metres/seconds.

Hope you understand better. Have a nice day guys!
(67)


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