Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - Data Sufficiency 1 (Q.No. 1)
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.
1.
What is the speed of the train whose length is 210 metres? | |
I. | The train crosses another train (Howrah Express/12869) of 300 metres length running in opposite direction in 10 seconds. |
II. | The train crosses another train (Howrah Express/12869) running in the same direction at the speed of 60 km/hr in 30 seconds. |
Answer: Option
Explanation:
| Time taken to cross the train, running in opposite directions |
= | (l1 + l2) | sec. |
| (u + v) |
 10 = |
(210 + 300) |
| (u + v) |
u + v = 51.
| Time taken to cross the train, running in same direction = | (l1 + l2) | sec. |
| (u - v) |
| 30 = |
(210 + 300) |
| (u - 60 x (5/18)) |
| u = |
 |
17 + | 50 |  m/sec. |
| 3 |
Thus, u and v can be obtained.
Correct answer is (E).
Discussion:
45 comments Page 3 of 5.
Vidhya said:
9 years ago
Yes, you are right @Gautam Kumar.
Hari said:
9 years ago
Only statement ii is sufficient to find the speed of the train asked in question but the statement I gives the length of the train. So we are using the length of train specified in statement I and substituting in statement II. So if statement I is not given we don't know the length of the train which we will substitute in statement II as per below.
Based on statement II.
Time taken to cross the train, running in same direction = (l1 + l2) / (u - v) (l1=given in question; l2= given in statement II; v= given in statement II; u = speed of train).
30 = (210 + 300) / (u - 60 x (5/18) ).
u = (17 +50/3) which is the speed of train asked in the question.
Therefore E is the correct answer.
Based on statement II.
Time taken to cross the train, running in same direction = (l1 + l2) / (u - v) (l1=given in question; l2= given in statement II; v= given in statement II; u = speed of train).
30 = (210 + 300) / (u - 60 x (5/18) ).
u = (17 +50/3) which is the speed of train asked in the question.
Therefore E is the correct answer.
(2)
Anuj said:
9 years ago
Actually, I have a doubt on this question a tree and having a length of 350 metre cross the bridge length 750 m. If the speed of the train is 55 kilometre per hour how much time will the train take to cross the bridge?
Can anyone solve this?
Can anyone solve this?
Kriti said:
8 years ago
Option (B) is the correct answer since statement II alone is sufficient to find the answer.
Priyanka said:
8 years ago
I think statement 2 is sufficient.
Dhanupatil said:
7 years ago
V in sec, how it is (5/18)?
Pankaj said:
7 years ago
Agree @A. Srikanth &@ditya. I miss length of the 2nd train. Thanks.
Sakshi Amrutkar said:
7 years ago
In the above given question where the length of a train is mentioned? please explain about it.
Rathod said:
7 years ago
u=606/5 not (17+50/3=101/3 it is not right).
Utkarsh saxena said:
7 years ago
Option E is correct because the length of the second train that is 300 m is given in statement 1 without it you cannot find the answer.
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