Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 16)
16.
A train travelling at a speed of 75 mph enters a tunnel 3
miles long. The train is 
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?
miles long. The train is 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?Answer: Option
Explanation:
| Total distance covered |
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 Time taken |
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| = 3 min. |
Discussion:
129 comments Page 2 of 13.
Anitha said:
1 decade ago
Yes Gaurav I agree with you..
Total distance covered = 7/2(tunnel)+1/4(length of train)+1/4(length of train since the rear part is to be considered emerging)= 4 miles
So total time taken = (4 miles / 75mph ) * 60 mins
= 3.2 mins
So the answer is [C]
Total distance covered = 7/2(tunnel)+1/4(length of train)+1/4(length of train since the rear part is to be considered emerging)= 4 miles
So total time taken = (4 miles / 75mph ) * 60 mins
= 3.2 mins
So the answer is [C]
Manni said:
1 decade ago
It will be 3mins.
Because total distance is 7/2 (tunnel) +1/4 (train).
When train starts entering tunnel there is nothing inside so why take 2 times.
Because total distance is 7/2 (tunnel) +1/4 (train).
When train starts entering tunnel there is nothing inside so why take 2 times.
Santhosh said:
1 decade ago
I did not get any clarity, I'm fluctuating between Gaurav and Manni.
Can any one explain?
Can any one explain?
Swetha said:
1 decade ago
Why don't we convert miles into meter in this problem? I'm very confused. Can anyone explain the solution clearly? please.
Swetha said:
1 decade ago
I didn't understand? can any one explain ?
Chaithanyadeepthi said:
1 decade ago
7/2= 3*2+1/2;
But i have one doubt
Why don't we convert miles into meters can anyone explain this?
But i have one doubt
Why don't we convert miles into meters can anyone explain this?
Uday said:
1 decade ago
In this problem we need time only that's why we are changing time only into minutes.
Aditya shukla said:
1 decade ago
Because train to pass through the tunnel from the moment the front enters to the moment the rear emerges. So we should add double the length of train then answer should be 3.2 min.
Gourab said:
1 decade ago
Yes aditya, you are absolutely rite, the answer should be 3. 2 min.
Supreet Sethi said:
1 decade ago
Answer is 3 min because.
Given is speed = 75 miles per hour
Total distance is 7/2 + 1/4 = 15/4
Distance is 15/4 because in question it is mentioned that calculate time from entry of tunnel to the point when train's rear left the tunnel.
Hope so this will help.
Given is speed = 75 miles per hour
Total distance is 7/2 + 1/4 = 15/4
Distance is 15/4 because in question it is mentioned that calculate time from entry of tunnel to the point when train's rear left the tunnel.
7/2 miles 1/4 miles
<---------------------------------><------->
_________________________________ train
entry of [ tunnel ]__________
tunnel [_________________________________]__________]--> -->
Hope so this will help.
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