Lessons

General Aptitude
1.2 Problems on Trains - Data Sufficiency 1

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Q.

What is the length of a running train?
1.The train crosses a man in 9 seconds. 
2.The train crosses a 240 metre long platform in 24 seconds.

View Answer

Correct choice: D

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).

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