Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 6)
6.
A train 240 m long passes a pole in 24 seconds. How long will it take to pass a platform 650 m long?
Answer: Option
Explanation:
| Speed = |  |
240 |  m/sec = 10 m/sec. |
| 24 |
 Required time = |
|
240 + 650 | sec = 89 sec. |
| 10 |
Discussion:
202 comments Page 7 of 21.
Kartikey patel said:
1 decade ago
I think in question ask the time taken for only bridge 650. Then why we add both?
HARI said:
1 decade ago
Dudes,
Actually the length is calculated along with the train only as (650+240). The passing of the platform is for the train, so that, train tail has to pass the platform; Henceforth,
(Train+ Platform)is correct
Actually the length is calculated along with the train only as (650+240). The passing of the platform is for the train, so that, train tail has to pass the platform; Henceforth,
(Train+ Platform)is correct
Umesh said:
1 decade ago
A train 240 m long passes a pole in 24 seconds. How long will it take to pass a platform 650 m long?
=====> for the tail of train to clear the platform it has to pass its own length + platform length.(240+650=890 m)
for 240 m. -- 24 sec.
for 890 m
by observation 890 is @ 4 times (some less) to 240
so time is also @ 4 times of 24 (some less) i,e. 96
from options 89 is @96 & somewhat less.
=====> for the tail of train to clear the platform it has to pass its own length + platform length.(240+650=890 m)
for 240 m. -- 24 sec.
for 890 m
by observation 890 is @ 4 times (some less) to 240
so time is also @ 4 times of 24 (some less) i,e. 96
from options 89 is @96 & somewhat less.
Suki said:
1 decade ago
Neetu's explanation s very nice.
Viji said:
1 decade ago
Neetu your explanation cleared my doubt. Thanks.
Devanshu said:
1 decade ago
Its not mentioned in ques that train passes pole and platform both. There is no need to add 240 with 650.
Tasauar rabani said:
1 decade ago
Neetus explanation is excelent.
Kavi said:
1 decade ago
@Kartikey Patel & Devanshu
First Me too Think like this
if
train 240 m long passes a pole in 24 seconds.
i.e 240 m : 24 sec
then 650 m : ? sec
650*24/240=65
and the ans is 65sec
....
After Saiyam Explanation i got clearly...
bfe netu he expn.
"so we include train length utill its last coach passing the platform.
time considered up to its last coach left the platform."
Thanks...
First Me too Think like this
if
train 240 m long passes a pole in 24 seconds.
i.e 240 m : 24 sec
then 650 m : ? sec
650*24/240=65
and the ans is 65sec
....
After Saiyam Explanation i got clearly...
bfe netu he expn.
"so we include train length utill its last coach passing the platform.
time considered up to its last coach left the platform."
Thanks...
Hannan said:
1 decade ago
By the information given, can you find out the length of pole?plz inform me.
The Guide said:
1 decade ago
For problems on trains for most of the problems we use one formulae
time=(l1+l2)/s1+s2
for eg in the above problem
given length of train 240m and time 24 sec then speed=10m/sec
given length of platform 650
their is no speed s2 because platform is a stationary object
so substitue all the values in above formulae
we get time t=(240+650)/10= 89sec
time=(l1+l2)/s1+s2
for eg in the above problem
given length of train 240m and time 24 sec then speed=10m/sec
given length of platform 650
their is no speed s2 because platform is a stationary object
so substitue all the values in above formulae
we get time t=(240+650)/10= 89sec
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