Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 18)
18.
A 300 metre long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?
Answer: Option
Explanation:
| Speed = |  |
300 |  |
m/sec = | 50 | m/sec. |
| 18 | 3 |
Let the length of the platform be x metres.
| Then, | |
x + 300 | |
= | 50 |
| 39 | 3 |
3(x + 300) = 1950
x = 350 m.
Discussion:
39 comments Page 4 of 4.
Akash said:
5 years ago
50/3 * 21.
21*50 = 1050,
1050/3 = 350.
21*50 = 1050,
1050/3 = 350.
(2)
Udaya said:
5 years ago
According to me;
300m long train cross-platform in 39 sec.
Cross pole in 18 sec (39-18= 21sec).
(Cross-Platform means platform +train)
(Cross Pole means only train length).
Extra time it takes 21 sec.
"18 sec ------ 300m.
21sec -------???? M.
21/18 * 300 = 350m.
300m long train cross-platform in 39 sec.
Cross pole in 18 sec (39-18= 21sec).
(Cross-Platform means platform +train)
(Cross Pole means only train length).
Extra time it takes 21 sec.
"18 sec ------ 300m.
21sec -------???? M.
21/18 * 300 = 350m.
(26)
Hadhik said:
5 years ago
I am not getting. Please explain.
(1)
Kirtijyoti said:
5 years ago
D should be the answer. It is not given a train is moving at a uniform speed. So crossing the pole or platform the speed won't be uniform as per the question. So data is inadequate.
(2)
Kushi said:
4 years ago
Did anyone please explain it clearly?
(4)
Santosh Kumar said:
2 years ago
Distance = 300m,
Time = 18.
Speed = Distance/Time.
= 300/18,
= 50/3.
Time = 18.
Speed = Distance/Time.
= 300/18,
= 50/3.
Bibek Nandy said:
2 years ago
300/18 = 50/3.
50/3x39 = 50x13 = 650.
650-300 = 350.
50/3x39 = 50x13 = 650.
650-300 = 350.
(6)
Manojsankar said:
1 year ago
@All.
Here, I am confused, why we take the speed of crossing the pole instead of crossing the speed of the platform? Anyone, please explain to me.
Here, I am confused, why we take the speed of crossing the pole instead of crossing the speed of the platform? Anyone, please explain to me.
(13)
Loki said:
3 months ago
@All.
Usually take 300+x and 300+y for platform and signal respectively but if we go by this there isn't enough data they have taken the pole as the stationery object as the beginning that is y it is so confusing they haven't mentioned something like that and did it.
Usually take 300+x and 300+y for platform and signal respectively but if we go by this there isn't enough data they have taken the pole as the stationery object as the beginning that is y it is so confusing they haven't mentioned something like that and did it.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers