Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - Data Sufficiency 2 (Q.No. 1)
Directions to Solve
Each of the questions given below consists of a question followed by three statements. You have to study the question and the statements and decide which of the statement(s) is/are necessary to answer the question.
1.
What is the speed of the train? | |
I. | The train crosses a signal pole in 18 seconds. |
II. | The train crosses a platform of equal length in 36 seconds. |
III. | Length of the train is 330 metres. |
Answer: Option
Explanation:
Let the speed of the train be x metres/sec.
| Time taken to cross a signal pole = | Length of the train |
| Speed of the train |
| Time taken to cross a platform = | (Length of the train + Length of the Platform) |
| Speed of the train |
Length of train = 330 m.
| I and III give, 18 = | 330 |  x = |
330 | m/sec = | 55 | m/sec. |
| x | 18 | 3 |
| II and III give, 36 = | 2 x 330 | x = |
660 | m/sec = | 55 | m/sec. |
| x | 36 | 3 |
Correct answer is (D).
Discussion:
21 comments Page 2 of 3.
Vivek kumar said:
1 decade ago
According to me any 2 of 3 are sufficient to find out the velocity of train. So given answer is wrong.
(1)
Arun said:
6 years ago
Why 330 is multiplied by 2?
(1)
Anksuh said:
6 years ago
@All.
By comparing 1 & 2 speed becomes length/18 in both cases so we can't solve them. Therefore given option is correct.
By comparing 1 & 2 speed becomes length/18 in both cases so we can't solve them. Therefore given option is correct.
(1)
Narayana Bojja said:
9 years ago
No, the correct answer is E. Because we can use statements I, II to determine train speed.
Ashish said:
1 day ago
@Nikitha 27x - 13x = 14x then.
So, 250/14 = 17.87 also you can right as 125/ 7 = 17.87.
So, 250/14 = 17.87 also you can right as 125/ 7 = 17.87.
Neha Priya said:
7 years ago
Either 2 can be used but only 3 cannot give the speed of train so, the answer should be E.
Manoj said:
8 years ago
Why 330 is multiplied by 2?
Fiza said:
9 years ago
Yes, the answer is D. Thanks @Shubham.
Technista said:
1 decade ago
I & II can also be used.
We'll get 2 equations. Since length of platform is equal to the length of train. According to me the answer is wrong.
We'll get 2 equations. Since length of platform is equal to the length of train. According to me the answer is wrong.
Gurucharan said:
1 decade ago
Answer given is correct.
They are implying that I&III or I&III can be used but not I and II.
They are implying that I&III or I&III can be used but not I and II.
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