Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - Data Sufficiency 1 (Q.No. 3)
Directions to Solve

Each of the questions given below consists of a statement and / or a question and two statements numbered I and II given below it. You have to decide whether the data provided in the statement(s) is / are sufficient to answer the given question. Read the both statements and

  • Give answer (A) if the data in Statement I alone are sufficient to answer the question, while the data in Statement II alone are not sufficient to answer the question.
  • Give answer (B) if the data in Statement II alone are sufficient to answer the question, while the data in Statement I alone are not sufficient to answer the question.
  • Give answer (C) if the data either in Statement I or in Statement II alone are sufficient to answer the question.
  • Give answer (D) if the data even in both Statements I and II together are not sufficient to answer the question.
  • Give answer(E) if the data in both Statements I and II together are necessary to answer the question.

3.

What is the length of a running train?

I. 

The train crosses a man in 9 seconds.

 II. 

The train crosses a 240 metre long platform in 24 seconds.

I alone sufficient while II alone not sufficient to answer
II alone sufficient while I alone not sufficient to answer
Either I or II alone sufficient to answer
Both I and II are not sufficient to answer
Both I and II are necessary to answer
Answer: Option
Explanation:

Time taken by train to cross a man = Length of train       Speed = l ....(i)
Speed of train 9

Time taken by train
to cross a platform =
(Length of train +
Length of platform)
     Speed = l + 240 ....(ii)
Speed of train 24

From (i) and (ii), we get l = l + 240 .
9 24

Thus, l can be obtained. So both I and II are necessary to get the answer.

The correct answer is (E).

Discussion:
16 comments Page 2 of 2.

Ajay said:   1 decade ago
The speed of the train is given but nothing is mentioned about the speed of the man.

How can it be solved unless condition about the man is given?

Linux said:   1 decade ago
Can you please explain what the answer to the equation is I chose option B on the premise that the length of the train is 10 m.

How would we solve the equation please?

Yogitha said:   1 decade ago
Please give some instruction about train problems?

Prerana said:   1 decade ago
Speed of man is not mentioned. What if he is also moving with some speed. So answer should be D.

Viresh said:   1 decade ago
Here same train is crossing both man n d platform so d speed ll b same in both d cases so optn E is correct

Ambika said:   1 decade ago
Ambika
Please any help me; I can't understand how it is possible , because here they didn't give any comment about speed . How can we equate both speeds (Man &Train). I think option D is correct. Anybody can understood please explain to me.


Post your comments here:

Your comments will be displayed after verification.