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.
Pankaj said:
8 years ago
Agree @A. Srikanth &@ditya. I miss length of the 2nd train. Thanks.
Dhanupatil said:
8 years ago
V in sec, how it is (5/18)?
Priyanka said:
8 years ago
I think statement 2 is sufficient.
Raja said:
1 decade ago
@Kausar and @Vivek without knowing the length of the other train how would you find velocity of other train ?
Senthil said:
1 decade ago
Thanks Sundar
Aditya Nath said:
1 decade ago
The question asks only for the speed of train which is 210m long and nothing of the Howrah Exp./12869... So statement II is sufficient alone.
Akanksha said:
1 decade ago
@Aditya is rite.
Gautam Kumar said:
1 decade ago
I don't think that option E is right. According to me option D is correct. This is because in the option I & II given in question it is specially mentioned Train number & Train name i.e. Howrah Express 12869. Now what I want to say that the same train can't run in both same & opposite direction at one time.
Rakshit said:
1 decade ago
We can find speed by Ist statement by using formula s=d/t
d=300+210=510
t=10 sec
s=51m/sec.
Using relative speed formula we can
S1+S2=D1/T
S1=x
S2=51m/sec
D1=210
T=10 sec.
d=300+210=510
t=10 sec
s=51m/sec.
Using relative speed formula we can
S1+S2=D1/T
S1=x
S2=51m/sec
D1=210
T=10 sec.
A.srikanth said:
1 decade ago
What @Sunder said it is right.
And what @GAUTHM KUMAR said is just like he showing his sense of humor. The answer E is correct.
And coming to @Adithya.
With out knowing the length of second train how you are going to find speed of first train ?
And what @GAUTHM KUMAR said is just like he showing his sense of humor. The answer E is correct.
And coming to @Adithya.
With out knowing the length of second train how you are going to find speed of first train ?
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