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:
237 comments Page 20 of 24.
Hima said:
8 years ago
Ratio of their speed = total distance travelled/total time taken= total speed.
(27x+17 y)/23 = (x+y),
27x+17y = 23x+23y,
4x = 6y,
x/y = 6/4,
3:2.
(27x+17 y)/23 = (x+y),
27x+17y = 23x+23y,
4x = 6y,
x/y = 6/4,
3:2.
RAHUL tulskar said:
8 years ago
Look at this simplest ans.
Take both crossing time as an x y.
27as x 17 as y.
Then,
27x+17y/x+y=23.
27x+17y=23x+23y.
27x-23x=17y-23y.
4x =6y.
Or
XY=4/6or 2/3 get it.
Take both crossing time as an x y.
27as x 17 as y.
Then,
27x+17y/x+y=23.
27x+17y=23x+23y.
27x-23x=17y-23y.
4x =6y.
Or
XY=4/6or 2/3 get it.
Anuj said:
8 years ago
23-27:23-17.
4:6
2:3
4:6
2:3
Ashfaq said:
8 years ago
Distance /time = speed.
but here in solution
distance /time = time (i.e 23 seconds )
How it is possible?
but here in solution
distance /time = time (i.e 23 seconds )
How it is possible?
UdoNe said:
8 years ago
27x+17y=DISTANCE.
x+y=SPEED,
23=TIME.
x+y=SPEED,
23=TIME.
Latz said:
8 years ago
What if both trains will be in the same direction?
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).
Samara said:
8 years ago
Let the distance of platform be x.
Then speed1= x/27-23 and speed2= x/23-17,
So, the ratio of speed is 3:2.
Then speed1= x/27-23 and speed2= x/23-17,
So, the ratio of speed is 3:2.
Pankj said:
8 years ago
One doubt.
According to this answer train taking 27 sec to cross the man having more speed than train taking 17 sec. As per my knowledge train taking more time having less speed anyone can explain this ?
According to this answer train taking 27 sec to cross the man having more speed than train taking 17 sec. As per my knowledge train taking more time having less speed anyone can explain this ?
Sujay said:
8 years ago
---23------>----4-----|27
23<--6sec---|<---17sec----- Man
Train which takes 27 sec to cross a man takes 4 more seconds to cross man(27-23)
Train which takes 17 sec to cross a man takes 6 more seconds to cross train(23-17)
Let distance between crossover of train and man standing to be X
Speed ratio=x/4:x/6.
i,e 3:2.
23<--6sec---|<---17sec----- Man
Train which takes 27 sec to cross a man takes 4 more seconds to cross man(27-23)
Train which takes 17 sec to cross a man takes 6 more seconds to cross train(23-17)
Let distance between crossover of train and man standing to be X
Speed ratio=x/4:x/6.
i,e 3:2.
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