Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - Data Sufficiency 2 (Q.No. 2)
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.
2.
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. |
Answer: Option
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.)
Discussion:
13 comments Page 2 of 2.
Jessy said:
1 decade ago
Sorry I'm not clear with 125/7 please explain it. Thank you.
Chiku said:
1 decade ago
Here we assume that speed is x in both the cases and we just equate the two equation.
Preeti2009_delhi@yahoo.com said:
1 decade ago
x is the velocity of the train?125/7=17.85=velocity of the =x, in the second case,
While in the 1st case there is the tree thats why we will consider only the lengh of the train and actually we do not know that?
According to the 1st case speed of the train will be =l/13.
How we can say that the speed of the train is I,II?
While in the 1st case there is the tree thats why we will consider only the lengh of the train and actually we do not know that?
According to the 1st case speed of the train will be =l/13.
How we can say that the speed of the train is I,II?
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