Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - Data Sufficiency 1 (Q.No. 3)
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.
3.
What is the length of a running train? | |
I. | The train crosses a man in 9 seconds. |
II. | The train crosses a 240 metre long platform in 24 seconds. |
Answer: Option
Explanation:
| Time taken by train to cross a man = | Length of train |  Speed = |
l | ....(i) |
| Speed of train | 9 |
| Time taken by train to cross a platform = |
(Length of train + Length of platform) |
Speed = |
l + 240 | ....(ii) |
| Speed of train | 24 |
| From (i) and (ii), we get | l | = | l + 240 | . |
| 9 | 24 |
Thus, l can be obtained. So both I and II are necessary to get the answer.
The correct answer is (E).
Discussion:
16 comments Page 1 of 2.
Andy said:
6 years ago
x/9 = x+240/24.
24x = 9x + 2160.
15x = 2160.
x = 144.
24x = 9x + 2160.
15x = 2160.
x = 144.
(4)
Anty said:
6 years ago
x/9 = x+240/24.
24x = 9x + 2160.
15x = 2160.
x = 144.
24x = 9x + 2160.
15x = 2160.
x = 144.
(4)
Babu said:
1 decade ago
Train is passing a man.
Obviously the length of train will be the same as the required distance to pass that man as man has no length.
9 sec to pass the man (given).
24 sec to travel 240 m (given).
So, speed = 240/24 = 10 m/s.
Hence, Length of train = Distance travelled in 9s = 9*10 = 90 m.
Obviously the length of train will be the same as the required distance to pass that man as man has no length.
9 sec to pass the man (given).
24 sec to travel 240 m (given).
So, speed = 240/24 = 10 m/s.
Hence, Length of train = Distance travelled in 9s = 9*10 = 90 m.
(2)
Somil kumar bhadula said:
3 years ago
@All.
Here is the answer.
l/9 = l + 240/24,
l/9 = 9(l+10),
l/9 = 9l + 90,
10l = 91.
L= 91/10.
L = 9.5.
So, Answer is 9.5.
Here is the answer.
l/9 = l + 240/24,
l/9 = 9(l+10),
l/9 = 9l + 90,
10l = 91.
L= 91/10.
L = 9.5.
So, Answer is 9.5.
(2)
Nithyasri said:
1 decade ago
It's possible? I can't get it. Anyone else explain it.
(1)
Hernando said:
10 years ago
Answer should be D. No reason to assume the same speed of the train in both cases.
(1)
Nadeem said:
8 years ago
How 1st statement is true? Explain.
(1)
Ambika said:
1 decade ago
Ambika
Please any help me; I can't understand how it is possible , because here they didn't give any comment about speed . How can we equate both speeds (Man &Train). I think option D is correct. Anybody can understood please explain to me.
Please any help me; I can't understand how it is possible , because here they didn't give any comment about speed . How can we equate both speeds (Man &Train). I think option D is correct. Anybody can understood please explain to me.
Viresh said:
1 decade ago
Here same train is crossing both man n d platform so d speed ll b same in both d cases so optn E is correct
Prerana said:
1 decade ago
Speed of man is not mentioned. What if he is also moving with some speed. So answer should be D.
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