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 1 of 5.
Sundar said:
1 decade ago
Since in both statement reveals that the another train is "Howrah Express/12869" and its length is 300 meters.
Therefore, we can find the answer with I and II.
If it is not specified (if not included the another trains details specifically), it may be different trains and different length. In this case, the answer will be "Both I and II are not sufficient to answer".
Hope this will help you a little bit.
Therefore, we can find the answer with I and II.
If it is not specified (if not included the another trains details specifically), it may be different trains and different length. In this case, the answer will be "Both I and II are not sufficient to answer".
Hope this will help you a little bit.
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 ?
Gagan Mathur said:
1 decade ago
One of the trains speed is given. All we have to do is use the formula time to cross each other = (l1+l2)/(u-v).
Adsam said:
1 decade ago
II alone sufficient since only the speed of 210m train is asked.
Kausar Shamim said:
1 decade ago
According to me option E is not right as statement II alone is needed to find the speed of the train.
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