January 17, 2019 January 17, 2019 08:00 AM PST 09:00 AM PST Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL. January 19, 2019 January 19, 2019 07:00 AM PST 09:00 AM PST Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.
Author 
Message 
TAGS:

Hide Tags

Director
Joined: 08 Jun 2007
Posts: 546

An express train traveled at an average speed of 100
[#permalink]
Show Tags
25 Nov 2007, 20:00
Question Stats:
69% (03:16) correct 31% (03:05) wrong based on 398 sessions
HideShow timer Statistics
An express train traveled at an average speed of 100 kilometers per hour, stopping for 3 minutes after every 75 kilometers. A local train traveled at an average speed of 50 kilometers, stopping for 1 minute after every 25 kilometers. If the trains began traveling at the same time, how many kilometers did the local train travel in the time it took the express train to travel 600 kilometers? a. 300 b. 305 c. 307.5 d. 1200 e. 1236
Official Answer and Stats are available only to registered users. Register/ Login.



Director
Joined: 08 Jun 2007
Posts: 546

ok i figured it out..just got impatient..
people can give a shot!



Director
Joined: 12 Jul 2007
Posts: 843

Time for express train to travel 600 km =
600km/100kmh = 6 hours
600km/75 = 8 (7 stops + 1 for crossing the finish line)
total time = 6 hours 21 minutes
Distance traveled by local train in 6 hours 21 minutes:
300 km in 6 hours 12 minutes (6 hours of travel, 12 stops at 1 minute each)
so how far will it go in last 9 minutes?
9/60(50) = 9(50)/60 = 450/60 = 7.5
307.5 km in 6 hours 21 minutes
Answer: C



Manager
Status: folding sleeves up
Joined: 26 Apr 2013
Posts: 132
Location: India
Concentration: Finance, Strategy
GMAT 1: 530 Q39 V23 GMAT 2: 560 Q42 V26
GPA: 3.5
WE: Consulting (Computer Hardware)

Re: An express train traveled at an average speed of 100
[#permalink]
Show Tags
28 Aug 2014, 06:38
ashkrs wrote: An express train traveled at an average speed of 100 kilometers per hour, stopping for 3 minutes after every 75 kilometers. A local train traveled at an average speed of 50 kilometers, stopping for 1 minute after every 25 kilometers. If the trains began traveling at the same time, how many kilometers did the local train travel in the time it took the express train to travel 600 kilometers?
a. 300 b. 305 c. 307.5 d. 1200 e. 1236 Soln: we can do a guess work here to get to the right answer: Train A total time taken to cover 600 km = 6hrs + 21mins Train B will take 50*6 should be more than 300 (to 400 max) kms (so a/d/e are gone) so now b and C how many stops for 50kmph in 6 hrs = 12 21 12= 9 (odd number) ...answer should be in fraction Hence C



Intern
Joined: 08 Apr 2014
Posts: 2

Re: An express train traveled at an average speed of 100
[#permalink]
Show Tags
04 Sep 2014, 13:21
hey,
why would we count the last stop for the express train? it has already traveled 600 km the instant it gets to the last stop. therefore, shouldn't the number of 3 minute breaks be 6 rather than 7?
And thus, the express train travels 600 km in (8 intervals of 75km)*(45 minutes) + (6 stops)*(3 minutes) = 378 minutes
Then, counting the last stop of the local train, because it will need to travel some additional amount to fill the remaining time: The time it takes the local train to travel 300km: (12 intervals of 25km)*(30 minutes) + (11 stops)*(1 minute) = 371 minutes Which leaves 7 minutes left over allowing the local train to travel an additional: (7 minutes/60 minutes)*(50 km/hour) = 5.83 km
Which adds up to 12*25 + 5.83 = 305.83km traveled by the local train...



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 8789
Location: Pune, India

Re: An express train traveled at an average speed of 100
[#permalink]
Show Tags
04 Sep 2014, 20:43
siggarusfigs wrote: hey,
why would we count the last stop for the express train? it has already traveled 600 km the instant it gets to the last stop. therefore, shouldn't the number of 3 minute breaks be 6 rather than 7?
And thus, the express train travels 600 km in (8 intervals of 75km)*(45 minutes) + (6 stops)*(3 minutes) = 378 minutes
Then, counting the last stop of the local train, because it will need to travel some additional amount to fill the remaining time: The time it takes the local train to travel 300km: (12 intervals of 25km)*(30 minutes) + (11 stops)*(1 minute) = 371 minutes Which leaves 7 minutes left over allowing the local train to travel an additional: (7 minutes/60 minutes)*(50 km/hour) = 5.83 km
Which adds up to 12*25 + 5.83 = 305.83km traveled by the local train... At the end of 600 km, you have the 8th stop, not the 7th stop. That 8th stop has not been counted. Every 75 km, one stop. So after 150 km, you would have had 2 stops. So after 300 km, you would have had 4 stops and hence after 600 kms, 8 stops. Also, the question is a little ambiguous. The train travels at an average speed of 100 km/hr does not specify whether the stops are a part of the time taken to calculate average speed or not. Better verbiage would be "a train runs at an average speed of 100 km/hr and then stops for 3 mins after 75 km" and so on...
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



Manager
Joined: 26 Nov 2014
Posts: 91

Re: An express train traveled at an average speed of 100
[#permalink]
Show Tags
01 Aug 2015, 10:14
Express Train: 600 km > 6 hours (since 100 km/h) + stops * 3 min. stops = 600 / 75 = 8, but as it is an integer number, the last stop in km 600 is not a real stop, so it would be 7 stops so, time= 6 hours + 7 * 3 min. = 6 hours 21 min
Local Train: in 6 hours, it will make 300 km (since its speed is 50 km/hour) in 300 km it will have 300 / 25 stops = 12, 12 stops 1 min each = 12 min we have 6 hours 12 min, but we need to calculate how many km can it make in 6 hours 21 min, so 2112 = 9 min if 60 min it can make 50 km, 9 min it can make 7.5 km so, the distance is 300 + 7.5 = 307.5 km



Board of Directors
Joined: 17 Jul 2014
Posts: 2600
Location: United States (IL)
Concentration: Finance, Economics
GPA: 3.92
WE: General Management (Transportation)

Re: An express train traveled at an average speed of 100
[#permalink]
Show Tags
28 Mar 2016, 18:17
is there a faster way to solve this one? my approach: 600/100 = 6 hours without stops. 600/75 = 8, so it must have had 7 stops. 6*60+3*7 = 381 minutes.
the second train travels at 50 kmh in 360 min, it will travel 300 km. at every 25km, there will be a stop. so while travelling 300km, it will stop 300/25 = 12 full stops. so 12 minutes. we have 372 minutes to travel 300km. now..we need to know what distance the train will travel in the remaining 9 minutes.. 50/60 = 5/6 km/min. 5/6 * 9 = 15/2 = 7.5 so..the train travelled 300+7.5=307.5 km.



NonHuman User
Joined: 09 Sep 2013
Posts: 9416

Re: An express train traveled at an average speed of 100
[#permalink]
Show Tags
19 Dec 2018, 04:17
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources




Re: An express train traveled at an average speed of 100 &nbs
[#permalink]
19 Dec 2018, 04:17






