Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - Data Sufficiency 3 (Q.No. 2)
Directions to Solve
Each of these questions is followed by three statements. You have to study the question and all the three statements given to decide whether any information provided in the statement(s) is redundant and can be dispensed with while answering the given question.
2.
What is the length of a running train P crossing another running train Q? | |
I. | These two trains take 18 seconds to cross each other. |
II. | These trains are running in opposite directions. |
III. | The length of the train Q is 180 metres. |
Answer: Option
Explanation:
Let the length of the train P be x metres.
II. These trains are running in opposite directions.
III. Length of the train Q is 180 m.
| I. Time taken by P to cross Q = | (180 + x) |  18 = |
(180 + x) |
| Relative speed | Relative speed |
Thus, even with I, II and III, the answer cannot be obtained.
Correct answer is (E).
Discussion:
17 comments Page 1 of 2.
Sumit said:
1 decade ago
Since these two trains are running in opposite direction their relative speed should be (u+v). Therefore I think option D is the correct answer.
Arpit said:
1 decade ago
Why I can not do by this method?
D = 180/10 =10m.
And the distance of p.
D = s*t.
= 10*10= 100m.
D = 180/10 =10m.
And the distance of p.
D = s*t.
= 10*10= 100m.
J.karthik said:
1 decade ago
I can not understand.
J.karthik said:
1 decade ago
I cannot understand this method.
How this relative speed? Need more statement answer the question.
How this relative speed? Need more statement answer the question.
PRIYA said:
10 years ago
I think D is better answer we can obtain answer with I, II, III option.
Tushar said:
9 years ago
Yes, option D is the correct answer.
@bhi said:
9 years ago
Yes, I think with all the statements option's we can solve the question because total time is 18 sec. And the length of the second train is 180 m. So we can assume the speed of the first train then,
X+180/18 = 10 m/s.
180 is just the half part of total distance.
Correct me if I am taking wrong assumption.
X+180/18 = 10 m/s.
180 is just the half part of total distance.
Correct me if I am taking wrong assumption.
Prabir said:
9 years ago
If you want to find the length of the train then speed is required.
But here speed is not given so the answer is correct here that is E.
But here speed is not given so the answer is correct here that is E.
Sanjay said:
9 years ago
Which is the right answer?
Patel said:
8 years ago
Relative Velocity i.e. (u+v) is required for his question; which is not given here. So, option 'E' is the correct answer.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers