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PS : TRAIN (m09q09) [#permalink]
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27 Oct 2008, 00:59
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This topic is locked. If you want to discuss this question please repost it in the respective forum. The train consists of 6 carriages, 20 meters long each. The gap between the carriages is 1 meter. If the train is moving at a constant speed of 60 kmh, how much time will it take the train to run through a 1 kilometer tunnel? (A) \(1\frac{1}{8}\) minutes (B) \(1\frac{1}{2}\) minutes (C) \(1\frac{3}{4}\) minutes (D) 2 minutes (E) \(2\frac{1}{4}\) minutes Source: GMAT Club Tests  hardest GMAT questions
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Re: PS : TRAIN [#permalink]
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27 Oct 2008, 01:05
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1 1/8.
Total length of train = 20*6 + 5 (for gaps) = 125 meters.
Total distance required to cross tunnel = 1 km + 125m = 1.125 km.
Time required = (1.125/60)*60 minutes = 1.125 minutes = 1 1/8 minutes.



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Re: PS : TRAIN [#permalink]
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27 Oct 2008, 01:13
scthakur wrote: 1 1/8.
Total length of train = 20*6 + 5 (for gaps) = 125 meters.
Total distance required to cross tunnel = 1 km + 125m = 1.125 km.
Time required = (1.125/60)*60 minutes = 1.125 minutes = 1 1/8 minutes. i made silly mistake
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Re: PS : TRAIN [#permalink]
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27 Oct 2008, 01:18
amitdgr wrote: scthakur wrote: 1 1/8.
Total length of train = 20*6 + 5 (for gaps) = 125 meters.
Total distance required to cross tunnel = 1 km + 125m = 1.125 km.
Time required = (1.125/60)*60 minutes = 1.125 minutes = 1 1/8 minutes. i made silly mistake I am into the same boat. I make silly mistakes all in a hurry.



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Re: PS : TRAIN [#permalink]
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27 Oct 2008, 03:43
A  1 1/8
1125/(60 * 1000) * 60 = 9/8 = 1 1/8



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Re: PS : TRAIN (m09q09) [#permalink]
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06 Apr 2010, 05:02
amitdgr wrote: The train consists of 6 carriages, 20 meters long each. The gap between the carriages is 1 meter. If the train is moving at a constant speed of 60 kmh, how much time will it take the train to run through a 1 kilometer tunnel? (A) \(1\frac{1}{8}\) minutes (B) \(1\frac{1}{2}\) minutes (C) \(1\frac{3}{4}\) minutes (D) 2 minutes (E) \(2\frac{1}{4}\) minutes Source: GMAT Club Tests  hardest GMAT questions Train length = 6*20 + 1*5 = 125 m Total distance travelled = 1000 + 125 = 1125 m = 1.125 km = \(1\frac{1}{8}\) km time taken for 1 km = 1 min hence A.



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Re: PS : TRAIN (m09q09) [#permalink]
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06 Apr 2010, 08:52
Train Length = 6*20 + 5*1 = 125m Total Distance = Tunnel+Train = 1000m+125m = 1125 m = 1 1/8 Km Speed = 60KmpH = 1 Km/min So, it will take 1 1/8 min to travel the total distance.
Hence A.
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Re: PS : TRAIN (m09q09) [#permalink]
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08 Apr 2011, 07:03
amitdgr wrote: The train consists of 6 carriages, 20 meters long each. The gap between the carriages is 1 meter. If the train is moving at a constant speed of 60 kmh, how much time will it take the train to run through a 1 kilometer tunnel? (A) \(1\frac{1}{8}\) minutes (B) \(1\frac{1}{2}\) minutes (C) \(1\frac{3}{4}\) minutes (D) 2 minutes (E) \(2\frac{1}{4}\) minutes Source: GMAT Club Tests  hardest GMAT questions Length of the train = 6*20+5*1=125 meters Speed of the train = 60000/60 meters/min = 1000 meters/min Length of the tunnel = 1000 meters Total Distance = 1000+125=1125 meters Distance = Time*Speed 1125 = Time * 1000 \(Time = \frac{1125}{1000} = 1.125 = 1+ \frac{125}{1000} = 1+ \frac{1}{8}= 1\frac{1}{8}\) Ans: "A"
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Re: PS : TRAIN (m09q09) [#permalink]
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08 Apr 2011, 07:08
Total Length of train = 6 * 20 + 5 * 1 = 125 m  So time required = (1000 + 125)/{(60) * (1000)} hrs = 1125/1000 * 60/60 min = 1.125 min = 1 1/8 min Answer  A
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Re: PS : TRAIN (m09q09) [#permalink]
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12 Apr 2012, 07:05
amitdgr wrote: The train consists of 6 carriages, 20 meters long each. The gap between the carriages is 1 meter. If the train is moving at a constant speed of 60 kmh, how much time will it take the train to run through a 1 kilometer tunnel? (A) \(1\frac{1}{8}\) minutes (B) \(1\frac{1}{2}\) minutes (C) \(1\frac{3}{4}\) minutes (D) 2 minutes (E) \(2\frac{1}{4}\) minutes Source: GMAT Club Tests  hardest GMAT questions simple, but calculation is required... A is the answer clue to calculate it for 60km in 1 hr....and 125m long train to cross over 1km tunner will take another A mins... so calculate it for 1m  how much time from 60kmp and then apply for 125m length of train...n add 1+ the new value which gives A
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Re: PS : TRAIN (m09q09) [#permalink]
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12 Apr 2012, 07:38
a)
for me the best approach is convert speed from km\h to m\min and take the total length = Tunnel length + length of bogeys + gap in bogeys
just divide to get time in min
Glancing over the answers first to know that time required is in min can help



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Re: PS : TRAIN (m09q09) [#permalink]
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12 Apr 2012, 08:20
A quick calculation yields that the distance = 1.125 km Speed = 60kmph From options : distance in 1[1][/2] = 1.5 km Hence answer = A which is < 1[1][/2]
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Re: PS : TRAIN (m09q09) [#permalink]
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12 Apr 2012, 10:51
Length of train = 20+1+20+1+20+1+20+1+20+1+20 = 125 meters Speed of train = 1 km/minutes Tunnel Length = 1 km so train has to travel 1 km + its own length = 1.125 km
1.125 minutes require to cross the tunnel i.e. 1(1/8)
so answer is A.



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Re: PS : TRAIN (m09q09) [#permalink]
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05 Sep 2012, 06:00
A for me too Length is 125m Total distance travelled is length of tunnel + length of train = 1.125k To travel 60 km, train takes 60min To travel 1.125m, train takes 1.125 min. Hence A
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Re: PS : TRAIN (m09q09) [#permalink]
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06 Sep 2012, 09:47
I said, yeah it's 'A' then my mind said no way, you didn't do enough math...
Turns out I did.
Good question.



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Re: PS : TRAIN (m09q09) [#permalink]
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15 Apr 2013, 05:24



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Re: PS : TRAIN (m09q09) [#permalink]
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15 Apr 2013, 05:28
The train consists of 6 carriages, 20 meters long each. The gap between the carriages is 1 meter. If the train is moving at a constant speed of 60 kmh, how much time will it take the train to run through a 1 kilometer tunnel?
Net length of the train = 125m Length of train = 1000m
Net distance = train length + train's own leangth = 1125 m
The train travels 60 km in 1 hr => to cover 1125 m it takes 1.125 min = 1 1/8 Hence A



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Re: PS : TRAIN (m09q09) [#permalink]
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15 Apr 2013, 07:02
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amitdgr wrote: The train consists of 6 carriages, 20 meters long each. The gap between the carriages is 1 meter. If the train is moving at a constant speed of 60 kmh, how much time will it take the train to run through a 1 kilometer tunnel? (A) \(1\frac{1}{8}\) minutes (B) \(1\frac{1}{2}\) minutes (C) \(1\frac{3}{4}\) minutes (D) 2 minutes (E) \(2\frac{1}{4}\) minutes Source: GMAT Club Tests  hardest GMAT questions a) It helps to keep a few pointers in mind always, and one such pointer is that 60KM/hr = 1 KM/min b) For an object of "zero" length itself (like a point object), it would take 1 Minute to cross the tunnel c) The train has a length of 6*20 + 5*1 = 125 m, or 0.125 KM; Using pointer in "(a)" above, it would take 0.125 or 1/8 minutes Hence, total time to cross the tunnel is 1+ 1/8 minutes. Hence Option A.
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Re: PS : TRAIN (m09q09) [#permalink]
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15 Apr 2013, 07:06
Total distance to cover = length of train + length of tunnel = (20*6 + 5)/1000 + 1 Km = 1.125 km 1 km is traveled in 60 min > 1.125 km is traveled in 1.125 min = 1 + 1/8 min
Answer is A.



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Re: PS : TRAIN (m09q09) [#permalink]
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15 Apr 2013, 10:03
I will go with A We need to consider whole length of the train. the moment it enters the cave till last carriage leave the cave that will add another 0.125. Rest iOS just applying the formula.
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