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. January 20, 2019 January 20, 2019 07:00 AM PST 07:00 AM PST Get personalized insights on how to achieve your Target Quant Score.
Author 
Message 
TAGS:

Hide Tags

Senior Manager
Joined: 21 Oct 2013
Posts: 419

A woman is planning a trip that involves 3 connecting trains
[#permalink]
Show Tags
13 Jan 2014, 12:07
Question Stats:
62% (03:31) correct 38% (03:08) wrong based on 224 sessions
HideShow timer Statistics
A woman is planning a trip that involves 3 connecting trains that depart from Stations X, Y, and Z, respectively. The first train leaves Station X every hour, beginning at 6 a.m., and arrives at Station Y 1(3/4) hours later. The second train leaves Station Y every half hour, beginning at 9 a.m., and arrives at Station Z 2(1/3) hours later. The third train leaves Station Z every 45 minutes, beginning at 8 a.m. What is the least total amount of time the woman must spend waiting between trains if all trains depart and arrive on schedule, and if she arrives at Station Z no later than 3:30 p.m.? 15 minutes 25 minutes 1 hour 15 minutes 1 hour 40 minutes 4 hours 30 minutes OE Trains coming from X arrive at Y at 45 minutes past the hour. Trains leave Y on the hour and the halfhour. So minimum wait at Y will be 0:15. This could be 8:45 − 9:00 am, 9:45 − 10:00 am, 10:45 − 11:00 am, etc.
Trains from Y will reach Z at 20 and 50 minutes past the hour, with the first arriving at 11:20.
Trains leave Z at various times, creating waits as short as 10 minutes (12:2012:30) and as long as 40 minutes (11:5012:30).
For shortest total waiting time possible, need to combine a 15minute wait for the second train with a 10minute wait for third train.
This will happen if the woman takes the 8:00 train from X, the 10:00 train from Y, and the 12:30 train from Z. Hi, I found the situation of this question is not very clear.. I want to know how we can approach this, please.
Official Answer and Stats are available only to registered users. Register/ Login.




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

Re: A woman is planning a trip that involves 3 connecting trains
[#permalink]
Show Tags
02 Mar 2015, 01:28
goodyear2013 wrote: A woman is planning a trip that involves 3 connecting trains that depart from Stations X, Y, and Z, respectively. The first train leaves Station X every hour, beginning at 6 a.m., and arrives at Station Y 1(3/4) hours later. The second train leaves Station Y every half hour, beginning at 9 a.m., and arrives at Station Z 2(1/3) hours later. The third train leaves Station Z every 45 minutes, beginning at 8 a.m. What is the least total amount of time the woman must spend waiting between trains if all trains depart and arrive on schedule, and if she arrives at Station Z no later than 3:30 p.m.? 15 minutes 25 minutes 1 hour 15 minutes 1 hour 40 minutes 4 hours 30 minutes OE Trains coming from X arrive at Y at 45 minutes past the hour. Trains leave Y on the hour and the halfhour. So minimum wait at Y will be 0:15. This could be 8:45 − 9:00 am, 9:45 − 10:00 am, 10:45 − 11:00 am, etc.
Trains from Y will reach Z at 20 and 50 minutes past the hour, with the first arriving at 11:20.
Trains leave Z at various times, creating waits as short as 10 minutes (12:2012:30) and as long as 40 minutes (11:5012:30).
For shortest total waiting time possible, need to combine a 15minute wait for the second train with a 10minute wait for third train.
This will happen if the woman takes the 8:00 train from X, the 10:00 train from Y, and the 12:30 train from Z. Hi, I found the situation of this question is not very clear.. I want to know how we can approach this, please. Make a departure arrival diagram to minimize the waiting time. Attachment:
FullSizeRender.jpg [ 1.49 MiB  Viewed 3341 times ]
Trains depart from X at 6/7/8/9 and reach Y at 7:45/8:45/9:45 etc Trains depart from Y at 9/9:30/10/10:30 etc. This means a minimum wait of 15 mins is required at Y. They arrive at Z at 11:20/11:50/12:20/12:50. They depart from Z at 8/8:45/9:30/10:15/11/11:45/12:30 and so on. Note that if she arrives at Z at 20 mins past the hour, she will need to wait for at least 10 mins for 12:30/3:30 etc train. If she arrives at 50 mins past the hour, again she needs to wait for at least 10 mins to take the 2 o clock train. So anyway 10 mins at Z is a given. So minimum she will need to wait for 15+10 = 25 mins. This works out if she takes 8 o clock train from X, reaches Y at 9:45, takes 10 o clock train from Y and reaches Z at 12:20 and takes 12:30 train from Z. Answer (B)
_________________
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 >




Math Expert
Joined: 02 Sep 2009
Posts: 52267

Re: A woman is planning a trip that involves 3 connecting trains
[#permalink]
Show Tags
13 Jan 2014, 12:15
goodyear2013 wrote: A woman is planning a trip that involves 3 connecting trains that depart from Stations X, Y, and Z, respectively. The first train leaves Station X every hour, beginning at 6 a.m., and arrives at Station Y 1(3/4) hours later. The second train leaves Station Y every half hour, beginning at 9 a.m., and arrives at Station Z 2(1/3) hours later. The third train leaves Station Z every 45 minutes, beginning at 8 a.m. What is the least total amount of time the woman must spend waiting between trains if all trains depart and arrive on schedule, and if she arrives at Station Z no later than 3:30 p.m.? 15 minutes 25 minutes 1 hour 15 minutes 1 hour 40 minutes 4 hours 30 minutes OE Trains coming from X arrive at Y at 45 minutes past the hour. Trains leave Y on the hour and the halfhour. So minimum wait at Y will be 0:15. This could be 8:45 − 9:00 am, 9:45 − 10:00 am, 10:45 − 11:00 am, etc.
Trains from Y will reach Z at 20 and 50 minutes past the hour, with the first arriving at 11:20.
Trains leave Z at various times, creating waits as short as 10 minutes (12:2012:30) and as long as 40 minutes (11:5012:30).
For shortest total waiting time possible, need to combine a 15minute wait for the second train with a 10minute wait for third train.
This will happen if the woman takes the 8:00 train from X, the 10:00 train from Y, and the 12:30 train from Z. Hi, I found the situation of this question is not very clear.. I want to know how we can approach this, please. This is a reworded OG question: anairlinepassengerisplanningatripthatinvolvesthree108830.html
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Intern
Joined: 12 Oct 2014
Posts: 45
Location: India
Concentration: Finance, General Management
WE: Analyst (Investment Banking)

A woman is planning a trip that involves 3 connecting trains
[#permalink]
Show Tags
19 Jun 2015, 06:16
I would prefer back solving for this question. Reached Z @ 3:30 PM, from Y>Z it will take 140 minutes, so she should have started from Y @ 1:10 PM but trains from Y to Z leaves at every 30mins starting at 9am,therefore she should board into the train @1PM and wait at station Z for 10minutes for her next train from station Z. Now, X > Y journey:To reach Y at 1PM she should start from X by 11AM atleast as, journey time is 105minutes .If she will start from station X by 11AM then she will reach Y by 12:45 PM, hence will wait for 15minutes before she board into 1PM train from station Y. Total waiting time= 15+10=25 minutes. Hope that was helpful. Cheers, Gaurav



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

Re: A woman is planning a trip that involves 3 connecting trains
[#permalink]
Show Tags
13 Jan 2016, 18:36
kind of tricky one...but as bunuel said..looks like an og question... if passenger leaves at 8AM, then arrives at Y at 9:45AM, departs at 10AM, or waits 15 minutes (always 15 mins, since the timing is always 15 mins either behind or late) trains at Z depart at 8:45, 9:30, 10:15, 11:00, 11:45, 12:30, 1:15PM, 2PM, 2:45PM 8:45, 9:30, 10:15, and 11:00 can't be, so right away out. note that the train from Y to Z alone takes 2h20min, and train Y starts at 9AM. if starts at 9AM, then it will arrive at Z at 11:20, which makes 25 mins wait time at Z. if starts at 9:30 > arrives at 11:50  wait time  40 minutes. nope if starts at 10 > arrives at 12:20  wait time 10 minutes. if starts at 10:30 > arrives at 12:50 > wait time 25 minutes if starts at 11 > arrives at 1:20PM, wait time 40 minutes. if starts at 11:30 > arrives at 1:50 > wait time 10 minutes. if starts at 12 > arrives at 12:20 > wait time 25 mins. thus, the min time to wait would be 10 mins at Z. 15+10 = 25 can't be 15, since the time to wait at Y only is 15, and there is no such way that there is no wait time at Z.



Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2830

Re: A woman is planning a trip that involves 3 connecting trains
[#permalink]
Show Tags
19 Apr 2018, 15:58
goodyear2013 wrote: A woman is planning a trip that involves 3 connecting trains that depart from Stations X, Y, and Z, respectively. The first train leaves Station X every hour, beginning at 6 a.m., and arrives at Station Y 1(3/4) hours later. The second train leaves Station Y every half hour, beginning at 9 a.m., and arrives at Station Z 2(1/3) hours later. The third train leaves Station Z every 45 minutes, beginning at 8 a.m. What is the least total amount of time the woman must spend waiting between trains if all trains depart and arrive on schedule, and if she arrives at Station Z no later than 3:30 p.m.? 15 minutes 25 minutes 1 hour 15 minutes 1 hour 40 minutes 4 hours 30 minutes We see that the total wait time is the total time waiting at stations Y and Z assuming that she doesn’t have to wait at station X. Let’s also let the trains leaving at stations X, Y and Z be trains X, Y and Z, respectively. Assuming she arrives at station X exactly on the hour, except for arriving at 6 am at station X, she must wait 15 minutes at station Y for train Y. For example, if she catches train X at station X at 7 am, she will arrive at station Y at 8:45 am and catch train Y at 9 am. If she catches train X at station X at 8 am, she will arrive at station Y at 9:45 am and catch train Y at 10 am. We see that the minimum wait time at station Y is 15 minutes. Now let’s see how we can minimize the wait time at station Z. Since train Z leaves station Z every 45 minutes beginning at 8 am, train Z leaves station Z at 8 am, 8:45 am, 9:30 am, 10:15 am, 11 am, 11:45 am, 12:30 pm, etc. Also, since train Y takes 2 hours and 20 minutes to arrive at station Z and it leaves station Y every 30 minutes beginning at 9 am, train Y will arrive at station Z at 11:20 am, 11:50 am, 12:20 pm, etc. We see that the minimum wait time is 10 minutes if she can arrive at station Z at 12:20 pm and take train Z at 12:30 pm. Thus the minimum total wait time is 15 + 10 = 25 minutes. Answer: B
_________________
Jeffery Miller
Head of GMAT Instruction
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions




Re: A woman is planning a trip that involves 3 connecting trains &nbs
[#permalink]
19 Apr 2018, 15:58






