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 15 of 24.
Chanti said:
1 decade ago
I didn't understood why x+y is divided by the term 27x+17y... can any body help to explain clearly
Ranjitha said:
1 decade ago
@ chanti
its length=speed*time
so length of first train=27*x mts
and length of 2nd train= 17*y mts
its length=speed*time
so length of first train=27*x mts
and length of 2nd train= 17*y mts
Karma said:
4 years ago
Isn't it like X/Y = 4/6?
How come in the above solution like X/Y 6/4=3:2.
X=4 and Y=6 isn't it?
How come in the above solution like X/Y 6/4=3:2.
X=4 and Y=6 isn't it?
(6)
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.
Angel said:
8 years ago
@Latz.
If both trains will be in the same direction then the equation becomes:
(27x+17y)/(x-y).
If both trains will be in the same direction then the equation becomes:
(27x+17y)/(x-y).
K.kiran kumar said:
2 decades ago
I can't get this step
(27x+17y) / (x+y) = 23
Why we have to use this? can any one explain me.
(27x+17y) / (x+y) = 23
Why we have to use this? can any one explain me.
RAVI said:
1 decade ago
I can't get this step
(27x+17y) / (x+y) = 23
Why we have to use this? can any one explain me.
(27x+17y) / (x+y) = 23
Why we have to use this? can any one explain me.
Amit Jana said:
1 decade ago
#Krishna no this is not possible as you say. Then cross each other in 23 sec. Is have no sense?
Sourabh yadav said:
9 years ago
An alternative answer:
27 - 23 = 4.
27 - 17 = 6.
Take the square root of both 6 and 4
=> 3:2.
27 - 23 = 4.
27 - 17 = 6.
Take the square root of both 6 and 4
=> 3:2.
Abraham said:
6 years ago
The explanation are excellent, but we asked the the speed, so why we calculated the time taken?
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