Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 19)
19.
A train speeds past a pole in 15 seconds and a platform 100 m long in 25 seconds. Its length is:
Answer: Option
Explanation:
Let the length of the train be x metres and its speed by y m/sec.
| Then, | x | = 15  y = |
x | . |
| y | 15 |
 |
x + 100 | = | x |
| 25 | 15 |
15(x + 100) = 25x
15x + 1500 = 25x
1500 = 10x
x = 150 m.
Discussion:
55 comments Page 6 of 6.
Priya said:
2 decades ago
@pavan
Since we have declared x-distance,y-speed
According to the below given formula,
Time=Distance/speed
Here Train speed time is specified as 15 sec so,
15 =x/y
Since we have declared x-distance,y-speed
According to the below given formula,
Time=Distance/speed
Here Train speed time is specified as 15 sec so,
15 =x/y
Pavan said:
2 decades ago
Why we take x/y=15 can you please explain me?
Prabhakaran said:
2 decades ago
I can't understand step 2 mohanraj can you explain again clearly.
MOHANRAJ.A said:
2 decades ago
Assume that length is x meters.
Speed y m/sec, speed=distance/time
so, y=x/15.------------------------1.
Like the same calculate after crossing the platform
y=x+100/25--------------------2
LHS equal. So
x+100/25=x/15;
15(x+100)=25x
Then remaing sme as above.
Speed y m/sec, speed=distance/time
so, y=x/15.------------------------1.
Like the same calculate after crossing the platform
y=x+100/25--------------------2
LHS equal. So
x+100/25=x/15;
15(x+100)=25x
Then remaing sme as above.
Gowtham said:
2 decades ago
Please explain the question in detail.
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