Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - Data Sufficiency 2 (Q.No. 1)
Directions to Solve

Each of the questions given below consists of a question followed by three statements. You have to study the question and the statements and decide which of the statement(s) is/are necessary to answer the question.


1.

What is the speed of the train?

I. 

The train crosses a signal pole in 18 seconds.

II. 

The train crosses a platform of equal length in 36 seconds.

 III. 

Length of the train is 330 metres.

I and II only
II and III only
I and III only
III and either I or II only
Any two of the three
Answer: Option
Explanation:

Let the speed of the train be x metres/sec.

Time taken to cross a signal pole = Length of the train
Speed of the train

Time taken to cross a platform = (Length of the train + Length of the Platform)
Speed of the train

Length of train = 330 m.

I and III give, 18 = 330     x = 330 m/sec = 55 m/sec.
x 18 3

II and III give, 36 = 2 x 330     x = 660 m/sec = 55 m/sec.
x 36 3

Correct answer is (D).

Discussion:
21 comments Page 3 of 3.

Vivek kumar said:   1 decade ago
According to me any 2 of 3 are sufficient to find out the velocity of train. So given answer is wrong.
(1)


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