Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 4)
4.
Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:
Answer: Option
Explanation:
Let the speeds of the two trains be x m/sec and y m/sec respectively.
Then, length of the first train = 27x metres,
and length of the second train = 17y metres.
 |
27x + 17y | = 23 |
| x+ y |
27x + 17y = 23x + 23y
4x = 6y
| |
x | = | 3 | . |
| y | 2 |
Discussion:
233 comments Page 9 of 24.
Kaviarasan said:
9 years ago
Simple method:
A B
27 17
23 (Common time for A & B)
6 4
(23-17) (27-23)
3 : 2
A B
27 17
23 (Common time for A & B)
6 4
(23-17) (27-23)
3 : 2
Shield said:
9 years ago
How is it possible?
Kripita said:
9 years ago
Very well explained. Thanks.
Yarasani srinivas said:
9 years ago
TIME = DISTANCE /SPEED.
We don't know how much distance apart.
27x is train1 distance at which it crosses man.
17y is a 2nd train.
We know when they meet 23 sec.
23 = 27x + 17y/ x + y.
We don't know how much distance apart.
27x is train1 distance at which it crosses man.
17y is a 2nd train.
We know when they meet 23 sec.
23 = 27x + 17y/ x + y.
Phani said:
9 years ago
23 - 17 = 6.
27 - 23 = 4.
6 : 4 = 3 : 2.
27 - 23 = 4.
6 : 4 = 3 : 2.
Harry said:
9 years ago
I don't know its correct or not but I got the answer easily.
My step-- it's not telling about the speed so what we have here is 27 sec and 17 sec so its the ratio 27:17.
(27/9) = 3 : (17/9) =1.8 = 2.
So I got 3 : 2.
I don't know whether its right step or not, Please correct me, if it is wrong.
My step-- it's not telling about the speed so what we have here is 27 sec and 17 sec so its the ratio 27:17.
(27/9) = 3 : (17/9) =1.8 = 2.
So I got 3 : 2.
I don't know whether its right step or not, Please correct me, if it is wrong.
Arifshaikh said:
9 years ago
Try the rule of alligation.
It will take 30 sec.
It will take 30 sec.
Sarat said:
9 years ago
TIME = DISTANCE /SPEED.
We don't know how much distance apart
27x is train1 distance at which it crosses man
17y is 2nd train.
We know when they meet 23 sec.
23 = 27x + 17y/ x + y.
We don't know how much distance apart
27x is train1 distance at which it crosses man
17y is 2nd train.
We know when they meet 23 sec.
23 = 27x + 17y/ x + y.
Shrikant said:
9 years ago
@Narayan.
Your answer is good it is a bit easy method.
Your answer is good it is a bit easy method.
Heisenberg said:
9 years ago
Thanks @Narayan.
=> Guys use the method of mixture and allegation the answer is very much easy.
=> Guys use the method of mixture and allegation the answer is very much easy.
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