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Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 16)
Problems on Trains
16.
A train travelling at a speed of 75 mph enters a tunnel 31/2 miles long. The train is 1/4 mile long. How long does it take for the train to pass through the tunnel from the moment the front enters to the moment the rear emerges?
2.5 min
3 min
3.2 min
3.5 min
Answer: Option
Explanation:

Total distance covered
= ( 7 + 1 ( miles
2 4
= 15 miles.
4

Therefore Time taken
= ( 15 ( hrs
4 x 75
= 1 hrs
20
= ( 1 x 60 ( min.
20
= 3 min.

Discussion:
129 comments Page 8 of 13.
Sathish said:   9 years ago
Why this problem isn't convert the miles to meters or K.meters?
Priya said:   9 years ago
Please explain how come 60?
Priya said:   8 years ago
Can anyone explain 7/2+1/4=15/4 clearly?
Varinder said:   8 years ago
The total distance should be 7/2(tunnel)+1/4(while front entering in the tunnel)+1/4(while the rear is out of the tunnel) = 4 miles.
Prudhvi (palakol) said:   8 years ago
Simple 3.5 + 0.25 = 3.75,
3.75/75 = 0.05,
0.05 * 60 = 3.
Srj said:   8 years ago
Do we want to change miles to meters?
Milson marcelin said:   8 years ago
No because both are in miles.
Sunny Singla said:   8 years ago
Aas per my understanding it's 3.2.

Total distance cover by train in minutes : 75/60 = 1.25,
Total Distance need to cover : 3.5+.25(enter)+.25(exit) = 4 miles,
In one minute it cover : 1.25 m.
Minutes required to travel 4 miles = 4/1.25 = 3.2.
Chaitu said:   8 years ago
Y isn't miles converted to kms?
Sathish said:   8 years ago
Distance/speed = time.

So.

15/4 * 75 means it comes (15/4) /75 so 15*75/4 is the way is correct why 15/4*75? Explain.
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