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.

Hernando said:   10 years ago
Answer should be D. No reason to assume the same speed of the train in both cases.
(1)

Nithyasri said:   1 decade ago
It's possible? I can't get it. Anyone else explain it.
(1)

Andy said:   6 years ago
x/9 = x+240/24.
24x = 9x + 2160.
15x = 2160.
x = 144.
(4)

Anty said:   6 years ago
x/9 = x+240/24.
24x = 9x + 2160.
15x = 2160.
x = 144.
(4)

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

Nadeem said:   8 years ago
How 1st statement is true? Explain.
(1)


Post your comments here:

Your comments will be displayed after verification.