Lessons

General Aptitude
1.3 Problems on Trains - Data Sufficiency 2

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Q.

What is the speed of the train?

I. 

The train crosses a tree in 13 seconds.

II. 

The train crosses a platform of length 250 metres in 27 seconds.

 III. 

The train crosses another train running in the same direction in 32 seconds.

View Answer

Correct choice: A

Explanation:

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

Time taken to cross a tree = 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
I gives, 13 = l     13x.
x
II gives 27 = l + 250
x
13x + 250 = 27
x
x = 125 m/sec.
7

Thus I and II give the speed of the train.

The correct answer is (A.)

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