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 2 of 5.
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?
ANUSREE said:
3 months ago
Hi all.
I also first doubted that the 2nd alone is enough to find speed. But now I realise that the length of the train is given in 1st statement and we can’t find the speed without that length.
Hence, E is the correct option.
I also first doubted that the 2nd alone is enough to find speed. But now I realise that the length of the train is given in 1st statement and we can’t find the speed without that length.
Hence, E is the correct option.
(1)
Nisha Thakkar said:
9 months ago
@All.
We can directly find the speed of the first train by using the formula speed of the first train = relative speed + speed of the second train.
So, statement B alone is sufficient, therefore option B is right.
We can directly find the speed of the first train by using the formula speed of the first train = relative speed + speed of the second train.
So, statement B alone is sufficient, therefore option B is right.
(1)
Shanthkumar said:
6 years ago
Considering the direction of trains as per statement 1 i.e. opposite direction and statement 2 i.e the same direction so we need both statements to find train speed in both directions respectively.
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.
Vishal saini said:
2 years ago
Both I and II are necessary to answer.
Because statement I is needed to find the II statement.
Through this, we can find the speed of the train which we have to find.
Because statement I is needed to find the II statement.
Through this, we can find the speed of the train which we have to find.
Amit Kumar Verma said:
2 years ago
By solving the value of the speed of the train (u) is 101/3 and this doesn't satisfy statement 1.
So how the answer will be? Please explain me.
So how the answer will be? Please explain me.
(2)
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.
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.
Ramesh Kumar said:
5 years ago
Option E is correct. Because both statements are required for finding out the speed of both trains.
Thanks @Sundar and @Hari.
Thanks @Sundar and @Hari.
(1)
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